Biome changelog

This project follows Semantic Versioning. Due to the nature of Biome as a toolchain, it can be unclear what changes are considered major, minor, or patch. Read our guidelines to categorize a change.

New entries must be placed in a section entitled Unreleased. Read our guidelines for writing a good changelog entry.

Unreleased

Analyzer

Bug fixed

Fix #1748. Now for the following case we won't provide an unsafe fix for the noNonNullAssertion rule:
```
x[y.z!];
```
Contributed by @ah-yu
Fix #1081. The useAwait rule does not report for await...of. Contributed by @unvalley

CLI

New features

Add a new command biome migrate prettier. The command will read the file .prettierrc/prettier.json and .prettierignore and map its configuration to Biome's one. Due to the different nature of .prettierignore globs and Biome's globs, it's highly advised to make sure that those still work under Biome.
Now the file name printed in the diagnostics is clickable. If you run the CLI from your editor, you can Ctrl/⌘ + Click on the file name, and the editor will open said file. If row and columns are specified e.g. file.js:32:7, the editor will set the cursor right in that position. Contributed by @ematipico

Bug fixes

Don't process files under an ignored directory.

Previously, Biome processed all files in the traversed hierarchy, even the files under an ignored directory. Now, it completly skip the content of ignored directories.
Fix #1508 by excluding deleted files from being processed. Contributed by @ematipico
Fix #1173. Fix the formatting of a single instruction with commented in a control flow body to ensure consistency. Contributed by @mdm317
Fix overriding of javascript.globals. Contributed by @arendjr

Fix a bug where syntax rules weren't run when pulling the diagnostics. Now Biome will emit more parsing diagnostics, e.g.

check.js:1:17 parse/noDuplicatePrivateClassMembers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Duplicate private class member "#foo"

  > 1 │ class A { #foo; #foo }
      │                 ^^^^

Contributed by @ematipico

Enhancements

Removed a superfluous diagnostic that was printed during the linting/check phase of a file:

test.js check ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × The file contains diagnostics that needs to be addressed.

Contributed by @ematipico

Configuration

New features

Add the ability to resolve the configuration files defined inside extends from the node_modules/ directory.

If you want to resolve a configuration file that matches the specifier @org/configs/biome, then your package.json file must look this:
```
{
  "name": "@org/configs",
  "exports": {
    "./biome": "./biome.json"
  }
}
```
And the biome.json file that "imports" said configuration, will look like this:
```
{
  "extends": "@org/configs/biome"
}
```
Read the documentation to better understand how it works, expectations and restrictions.

Editors

Bug fixes

Fix a regression where ignored files where formatted in the editor. Contributed by @ematipico

Fix a bug where syntax rules weren't run when pulling the diagnostics. Now Biome will emit more parsing diagnostics, e.g.

check.js:1:17 parse/noDuplicatePrivateClassMembers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Duplicate private class member "#foo"

  > 1 │ class A { #foo; #foo }
      │                 ^^^^

Contributed by @ematipico

Formatter

New features

Biome now allows to format the package.json file. This is now the default behaviour and users can remove their workarounds. If you rely on other tools to format package.json, you'll have to ignore it via configuration. Contributed by @pattrickrice
New formatter option attributePosition that have similar behavior as Prettier singleAttributePerLine #1706. Contributed by @octoshikari
Add partial for .astro files. Biome is able to format the frontmatter of the Astro files. Contributed by @ematipico
```
---
- statement ( );
+ statement();
---

<div></div>
```
Add partial for .vue files. Biome is able to format the script block of Vue files. Contributed by @nhedger
```
<script setup lang="ts">
- statement ( );
+ statement();
</script/>

<template></template>
```

Bug fixes

Fix #1039. Check unicode width instead of number of bytes when checking if regex expression is a simple argument. Contributed by @kalleep

This no longer breaks.
```
s(/🚀🚀/).s().s();
```
Fix #1218, by correctly preserving empty lines in member chains. Contributed by @ah-yu

JavaScript APIs

Linter

BREAKING CHANGES

useNamingConvention and useFilenamingConvention now require identifiers to be in ASCII and without consecutive delimiters.

Set the requireAscii rule option to false to allow non-ASCII identifiers.
```
{
  "linter": {
    "rules": {
      "style": {
        "useNamingConvention": { "options": { "requireAscii": false } }
      },
      "nursery": {
        "useFilenamingConvention": { "options": { "requireAscii": false } }
      }
    }
  }
}
```
The following name is now invalid because it includes two underscores:
```
export const MY__CONSTANT = 0;
```
Note that we still allow consecutive leading and consecutive trailing underscores.

Contributed by @Conaclos

New features

Add the rule noSkippedTests, to disallow skipped tests:
```
describe.skip("test", () => {});
it.skip("test", () => {});
```
Contributed by @ematipico
Add the rule noFocusedTests, to disallow skipped tests:
```
describe.only("test", () => {});
it.only("test", () => {});
```
Contributed by @ematipico
Add rule useSortedClasses, to sort CSS utility classes:
```
- <div class="px-2 foo p-4 bar" />
+ <div class="foo·bar·p-4·px-2" />
```
Contributed by @DaniGuardiola
Add rule noUndeclaredependencies, to detect the use of dependencies that aren't present in the package.json

Enhancements

noUselessTernary now provides unsafe code fixes. Contributed by @vasucp1207
noApproximativeNumericConstant now provides unsafe code fixes and handle numbers without leading zero and numbers with digit separators.

The following numbers are now reported as approximated constants.
```
3.14_15; // PI
.4342; // LOG10E
```
Contributed by @Conaclos
noPrecisionLoss no longer reports number with extra zeros.

The following numbers are now valid.
```
.1230000000000000000000000;
1230000000000000000000000.0;
```
Contributed by @Conaclos
useNamingConvention now supports unicase letters (#1786).

unicase letters have a single case: they are neither uppercase nor lowercase. Previously, Biome reported names in unicase as invalid. It now accepts a name in unicase everywhere.

The following code is now accepted:
```
const 안녕하세요 = { 안녕하세요: 0 };
```
We still reject a name that mixes unicase characters with lowercase or uppercase characters: The following names are rejected:
```
const A안녕하세요 = { a안녕하세요: 0 };
```
Contributed by @Conaclos

Bug fixes

noInvalidUseBeforeDeclaration no longer reports valid use of binding patterns (#1648).

The rule no longer reports the following code:
```
const { a = 0, b = a } = {};
```
Contributed by @Conaclos
noUnusedVariables no longer reports used binding patterns (#1652).

The rule no longer reports a as unused the following code:
```
const { a = 0, b = a } = {};
export { b };
```
Contributed by @Conaclos
Fix #1651. noVar now ignores TsGlobalDeclaration. Contributed by @vasucp1207
Fix #1640. useEnumInitializers code action now generates valid code when last member has a comment but no comma. Contributed by @kalleep
Fix #1653. Handle a shorthand value in useForOf to avoid the false-positive case. Contributed by @togami2864
Fix #1656. useOptionalChain code action now correctly handles logical and chains where methods with the same name are invoked with different arguments:
```
- tags·&&·tags.includes('a')·&&·tags.includes('b')
+ tags?.includes('a') && tags.includes('b')
```
Contributed by @lucasweng
Fix #1704. Convert / to escaped slash \/ to avoid parsing error in the result of autofix. Contributed by @togami2864
Fix#1697. Preserve leading trivia in autofix of suppression rules. Contributed by @togami2864
Fix #603. Trim trailing whitespace to avoid double insertion. Contributed by @togami2864
Fix #1765. Now the rule noDelete doesn't trigger when deleting a dataset:
```
delete element.dataset.prop;
```
Contributed by @ematipico

Parser

Bug fixes

Fix #1728. Correctly parse the global declaration when the { token is on the line following the global keyword.

Now the following code is correctly parsed:
```
declare global
{ }

declare module foo {
  global
  { }
}
```
Contributed by @ah-yu
Fix #1730. Correctly parse delete expressions with operands that are not simple member expressions.
```
delete(a.b);
delete console.log(1);
delete(() => {});
```
Contributed by @printfn

1.5.3 (2024-01-22)

LSP

Bug fixes

Fix #1584. Ensure the LSP only registers the formatter once. Contributed by @nhedger
Fix #1589. Fix invalid formatting of own line comments when they were at the end of an import/export list. Contributed by @spanishpear

Configuration

Bug fixes

Override correctly the recommended preset (#1349).

Previously, if unspecified, Biome turned on the recommended preset in overrides. This resulted in reporting diagnostics with a severity level set to off. This in turn caused Biome to fail.

Now Biome won't switch on the recommended preset in overrides unless told to do so.

Contributed by @Conaclos
Don't format ignored files that are well-known JSONC files when files.ignoreUnknown is enabled (#1607).

Previously, Biome always formatted files that are known to be JSONC files (e.g. .eslintrc) when files.ignoreUnknown was enabled.

Contributed by @Conaclos

Formatter

Bug fixes

Fix #1178, where the line ending option wasn't correctly applied. Contributed by @ematipico
Fix #1571. Fix invalid formatting of nested multiline comments. Contributed by @ah-yu

Linter

Bug fixes

Fix #1575. noArrayIndexKey now captures array index value inside template literals and with string concatination. Contributed by @vasucp1207
Linter rules that inspect regexes now handle multibyte characters correctly (#1522).

Previously, noMisleadingCharacterClass, noMultipleSpacesInRegularExpressionLiterals, and noEmptyCharacterClassInRegex made Biome errors on multi-bytes characters. Multibyte characters are now handled correctly.

The following code no longer raises an internal error:
```
// Cyrillic characters
/[\u200E\u2066-\u2069]/gu;
```
Contributed by @Conaclos
useExhaustiveDependencies no longer made Biome errors in code TypeScript import equal declarations (#1194). Contributed by @Conaclos
Fix typo in the diagnostic of noNodejsModules. Contributed by @huseeiin

Parser

Bug fixes

Accept the const modifier for type parameter in method type signature (#1624).

The following code is now correctly parsed:
```
type Foo = {
  <const T>();
  method<const T>();
};
```
Contributed by @magic-akari
Correctly parse type arguments in expression(#1184).

The following code is now correctly parsed in typescript:
```
0 < (0 >= 1);
```
Contributed by @ah-yu

Website

New

Add a page that maps the Biome rule to its source. Contributed by @ematipico

Fixes

Generate Open Graph images based on the linked page. Contributed by @ematipico
Fix examples of the git hook page. Contributed by @9renpoto, @lmauromb, and @Conaclos
Fix dead and erroneous hyperlinks. Contributed by @Sec-ant and Conaclos

1.5.2 (2024-01-15)

CLI

Bug fixes

Fix #1512 by skipping verbose diagnostics from the count. Contributed by @ematipico
Correctly handle cascading include and ignore.

Previously Biome incorrectly included files that were included at tool level and ignored at global level. In the following example, file.js was formatted when it should have been ignored. Now, Biome correctly ignores the directory ./src/sub/.
```
❯ tree src
  src
  └── sub
      └── file.js

❯ cat biome.json
  {
    "files": { "ignore": ["./src/sub/"] },
    "formatter": { "include": ["./src"] }
  }
```
Contributed by @Conaclos
Don't emit verbose warnings when a protected file is ignored.

Some files, such as package.json and tsconfig.json, are protected. Biome emits a verbose warning when it encounters a protected file.

Previously, Biome emitted this verbose warning even if the file was ignored by the configuration. Now, it doesn't emit verbose warnings for protected files that are ignored.

Contributed by @Conaclos
overrides no longer affect which files are ignored. Contributed by @Conaclos
The file biome.json can't be ignored anymore. Contributed by @ematipico
Fix #1541 where the content of protected files wasn't returned to stdout. Contributed by @ematipico
Don't handle CSS files, the formatter isn't ready yet. Contributed by @ematipico

Configuration

Bug fixes

Fix 1440, a case where extends and overrides weren't correctly emitting the final configuration. Contributed by @arendjr
Correctly handle include when ignore is set (#1468). Contributed by @Conaclos

Previously, Biome ignored include if ignore was set. Now, Biome check both include and ignore. A file is processed if it is included and not ignored. If include is not set all files are considered included.

Formatter

Bug fixes

Fix placement of comments before * token in generator methods with decorators. #1537 Contributed by @ah-yu
Fix #1406. Ensure comments before the async keyword are placed before it. Contributed by @ah-yu
Fix #1172. Fix placement of line comment after function expression parentheses, they are now attached to first statement in body. Contributed by @kalleep
Fix #1511 that made the JavaScript formatter crash. Contributed @Conaclos

Linter

Enhancements

Add an unsafe code fix for noConsoleLog. Contributed by @vasucp1207
useArrowFunction no longer reports function in extends clauses or in a new expression. Contributed by @Conaclos

These cases require the presence of a prototype.
Add dependency variable names on error message when useExhaustiveDependencies rule shows errors. Contributed by @mehm8128

Bug fixes

The fix of useArrowFunction now adds parentheses around the arrow function in more cases where it is needed (#1524).

A function expression doesn't need parentheses in most expressions where it can appear. This is not the case with the arrow function. We previously added parentheses when the function appears in a call or member expression. We now add parentheses in binary-like expressions and other cases where they are needed, hopefully covering all cases.

Previously:
```
- f = f ?? function() {};
+ f = f ?? () => {};
```
Now:
```
- f = f ?? function() {};
+ f = f ?? (() => {});
```
Contributed by @Conaclos
Fix #1514. Fix autofix suggestion to avoid the syntax error in no_useless_fragments. Contributed by @togami2864

1.5.1 (2024-01-10)

CLI

Bug fixes

The diagnostics files/missingHandler are now shown only when the option --verbose is passed. Contributed by @ematipico
The diagnostics for protected files are now shown only when the option --verbose is passed. Contributed by @ematipico
Fix #1465, by taking in consideration the workspace folder when matching a pattern. Contributed by @ematipico
Fix #1465, by correctly process globs that contain file names. Contributed by @ematipico

Formatter

Bug fixes

Fix #1170. Fix placement of comments inside default switch clause. Now all line comments that have a preceding node will keep their position. Contributed by @kalleep

Linter

Bug fixes

Fix #1335. noUselessFragments now ignores code action on component props when the fragment is empty. Contributed by @vasucp1207
useConsistentArrayType was accidentally placed in the style rule group instead of the nursery group. It is now correctly placed under nursery.
Fix #1483. useConsistentArrayType now correctly handles its option. Contributed by @Conaclos
Fix #1502. useArrowFunction now correctly handle functions that return a (comma) sequence expression. Contributed by @Conaclos

Previously the rule made an erroneous suggestion:
```
- f(function() { return 0, 1; }, "");
+ f(() => 0, 1, "")
```
Now, the rule wraps any comma sequence between parentheses:
```
- f(function() { return 0, 1; }, "");
+ f(() => (0, 1), "")
```
Fix #1473: useHookAtTopLevel now correctly handles React components and hooks that are nested inside other functions. Contributed by @arendjr

1.5.0 (2024-01-08)

Biome now scores 97% compatibility with Prettier and features more than 180 linter rules.

Analyzer

CLI

New features

Biome now shows a diagnostic when it encounters a protected file. Contributed by @ematipico
The command biome migrate now updates the $schema if there's an outdated version.
The CLI now takes in consideration the .gitignore in the home directory of the user, if it exists. Contributed by @ematipico
The biome ci command is now able to print GitHub Workflow Commands when there are diagnostics in our code. Contributed by @nikeee This might require setting the proper permissions on your GitHub action:
```
permissions:
  pull-requests: write
```
The commands format, lint, check and ci now accept two new arguments: --changed and --since. Use these options with the VCS integration is enabled to process only the files that were changed. Contributed by @simonxabris
```
biome format --write --changed
```
Introduced a new command called biome explain, which has the capability to display documentation for lint rules. Contributed by @kalleep
You can use the command biome explain to print the documentation of lint rules. Contributed by @kalleep
```
biome explain noDebugger
biome explain useAltText
```
You can use the command biome explain to print the directory where daemon logs are stored. Contributed by @ematipico
```
biome explain daemon-logs
```
Removed the hard coded limit of 200 printable diagnostics. Contributed by @ematipico

Bug fixes

Fix #1247, Biome now prints a warning diagnostic if it encounters files that can't handle. Contributed by @ematipico

You can ignore unknown file types using the files.ignoreUnknown configuration in biome.json:
```
{
  "files": {
    "ignoreUnknown": true
  }
}
```
Or the --files-ignore-unknown CLI option:
```
biome format --files-ignore-unknown=true --write .
```
Fix #709 and #805 by correctly parsing .gitignore files. Contributed by @ematipico
Fix #1117 by correctly respecting the matching. Contributed by @ematipico
Fix #691 and #1190, by correctly apply the configuration when computing overrides configuration. Contributed by @ematipico

Configuration

New features

Users can specify git ignore patterns inside ignore and include properties, for example it's possible to allow list globs of files using the ! character:

{
  "files": {
    "ignore": [
      "node_modules/**",
      "!**/dist/**" // this is now accepted and allow files inside the `dist` folder
    ]
  }
}

Editors

New features

The LSP registers formatting without the need of using dynamic capabilities from the client.

This brings formatting services to the editors that don't support or have limited support for dynamic capabilities.

Formatter

Bug fixes

Fix #1169. Account for escaped strings when computing layout for assignments. Contributed by @kalleep
Fix #851. Allow regular function expressions to group and break as call arguments, just like arrow function expressions. #1003 Contributed by @faultyserver
Fix #914. Only parenthesize type-casted function expressions as default exports. #1023 Contributed by @faultyserver
Fix #1112. Break block bodies in case clauses onto their own lines and preserve trailing fallthrough comments. #1035 Contributed by @faultyserver
Fix RemoveSoftLinesBuffer behavior to also removed conditional expanded content, ensuring no accidental, unused line breaks are included #1032 Contributed by @faultyserver
Fix #1024. Allow JSX expressions to nestle in arrow chains #1033 Contributed by @faultyserver
Fix incorrect breaking on the left side of assignments by always using fluid assignment. #1021 Contributed by @faultyserver
Fix breaking strategy for nested object patterns in function parameters #1054 Contributed by @faultyserver
Fix over-indention of arrow chain expressions by simplifying the way each chain is grouped #1036, #1136, and #1162 Contributed by @faultyserver.
Fix "simple" checks for calls and member expressions to correctly handle array accesses, complex arguments to single-argument function calls, and multiple-argument function calls. #1057 Contributed by @faultyserver
Fix text wrapping and empty line handling for JSX Text elements to match Prettier's behavior. #1075 Contributed by @faultyserver
Fix leading comments in concisely-printed arrays to prevent unwanted line breaks. #1135 Contributed by @faultyserver
Fix best_fitting and interned elements preventing expansion propagation from sibling elements. #1141 Contributed by @faultyserver
Fix heuristic for grouping function parameters when type parameters with constraints are present. #1153. Contributed by @faultyserver.
Fix binary-ish and type annotation handling for grouping call arguments in function expressions and call signatures. #1152 and #1160 Contributed by @faultyserver
Fix handling of nestled JSDoc comments to preserve behavior for overloads. #1195 Contributed by @faultyserver
Fix #1208. Fix extraction of inner types when checking for simple type annotations in call arguments. #1195 Contributed by @faultyserver
Fix #1220. Avoid duplicating comments in type unions for mapped, empty object, and empty tuple types. #1240 Contributed by @faultyserver
Fix #1356. Ensure if_group_fits_on_line content is always written in RemoveSoftLinesBuffers. #1357 Contributed by @faultyserver
Fix #1171. Correctly format empty statement with comment inside arrow body when used as single argument in call expression. Contributed by @kalleep
Fix #1106. Fix invalid formatting of single bindings when Arrow Parentheses is set to "AsNeeded" and the expression breaks over multiple lines. #1449 Contributed by @faultyserver

JavaScript APIs

Linter

Promoted rules

New rules are incubated in the nursery group. Once stable, we promote them to a stable group. The following rules are promoted:

a11y/noAriaHiddenOnFocusable
a11y/useValidAriaRole
complexity/useRegexLiterals
suspicious/noImplicitAnyLet
style/noDefaultExport

New features

Add useExportType that enforces the use of type-only exports for types. Contributed by @Conaclos

  interface A {}
  interface B {}
  class C {}

- export type { A, C }
+ export { type A, C }

- export { type B }
+ export type { B }

Add useImportType that enforces the use of type-only imports for types. Contributed by @Conaclos

- import { A, B } from "./mod.js";
+ import { type A, B } from "mod";
  let a: A;
  const b: B = new B();

Also, the rule groups type-only imports:

- import { type A, type B } from "./mod.js";
+ import type { A, B } from "./mod.js";

Add useFilenamingConvention, that enforces naming conventions for JavaScript and TypeScript filenames. Contributed by @Conaclos

By default, the rule requires that a filename be in camelCase, kebab-case, snake_case, or matches the name of an export in the file. The rule provides options to restrict the allowed cases.
Add useNodejsImportProtocol that enforces the use of the node: protocol when importing Node.js modules. Contributed by @2-NOW, @vasucp1207, and @Conaclos
```
- import fs from "fs";
+ import fs from "node:fs";
```
Add useNumberNamespace that enforces the use of the Number properties instead of the global ones.
```
- parseInt;
+ Number.parseInt;
- - Infinity;
+ Number.NEGATIVE_INFINITY;
```
Add useShorthandFunctionType that enforces using function types instead of object type with call signatures. Contributed by @emab, @ImBIOS, and @seitarof
```
- interface Example {
-   (): string;
- }
+ type Example = () => string
```


- Add [noNodejsModules](https://biomejs.dev/linter/rules/no-nodejs-modules), that disallows the use of _Node.js_ modules. Contributed by @anonrig, @ematipico, and @Conaclos

- Add [noInvalidUseBeforeDeclaration](https://biomejs.dev/linter/rules/no-invalid-use-before-declaration) that reports variables and function parameters used before their declaration. Contributed by @Conaclos

  ```js
  function f() {
    console.log(c); // Use of `c` before its declaration.
    const c = 0;
  }

Add useConsistentArrayType that enforces the use of a consistent syntax for array types. Contributed by @eryue0220

This rule will replace useShorthandArrayType. It provides an option to choose between the shorthand or the generic syntax.
Add noEmptyTypeParameters that ensures that any type parameter list has at least one type parameter. Contributed by @togami2864

This will report the following empty type parameter lists:
```
interface Foo<> {}
//           ^^
type Bar<> = {};
//      ^^
```
Add noGlobalEval that reports any use of the global eval. Contributed by @you-5805
Add noGlobalAssign that reports assignment to global variables. Contributed by @chansuke
```
Object = {}; // report assignment to `Object`.
```
Add noMisleadingCharacterClass that disallows characters made with multiple code points in character class. Contributed by @togami2864
Add noThenProperty that disallows the use of then as property name. Adding a then property makes an object thenable that can lead to errors with Promises. Contributed by @togami2864
Add noUselessTernary that disallows conditional expressions (ternaries) when simpler alternatives exist.
```
var a = x ? true : true; // this could be simplified to `x`
```

Enhancements

noEmptyInterface ignores empty interfaces that extend a type. Address #959 and #1157. Contributed by @Conaclos

This allows supporting interface augmentation in external modules as demonstrated in the following example:
```
interface Extension {
  metadata: unknown;
}

declare module "@external/module" {
  // Empty interface that extends a type.
  export interface ExistingInterface extends Extension {}
}
```
Preserve more comments in the code fix of useExponentiationOperator. Contributed by @Conaclos

The rule now preserves comments that follow the (optional) trailing comma.

For example, the rule now suggests the following code fix:
```
- Math.pow(
-    a, // a
-    2, // 2
-  );
+
+    a ** // a
+    2 // 2
+
```
<svg> element is now considered as a non-interactive HTML element (#1095). Contributed by @chansuke

This affects the following rules:
noMultipleSpacesInRegularExpressionLiterals has a safe code fix. Contributed by @Conaclos
useArrowFunction ignores expressions that use new.target. Contributed by @Conaclos
noForEach now reports only calls that use a callback with 0 or 1 parameter. Address #547. Contributed by @Conaclos

Bug fixes

Fix #1061. noRedeclare no longer reports overloads of export default function. Contributed by @Conaclos

The following code is no longer reported:

export default function(a: boolean): boolean;
export default function(a: number): number;
export default function(a: number | boolean): number | boolean {
  return a;
}

Fix #651, useExhaustiveDependencies no longer reports out of scope dependencies. Contributed by @kalleep

The following code is no longer reported:
```
let outer = false;

const Component = ({}) => {
  useEffect(() => {
    outer = true;
  }, []);
}
```

Fix #1191. noUselessElse now preserve comments of the else clause. Contributed by @Conaclos

For example, the rule suggested the following fix:

  function f(x) {
    if (x <0) {
      return 0;
    }
-   // Comment
-   else {
      return x;
-   }
  }

Now the rule suggests a fix that preserves the comment of the else clause:

  function f(x) {
    if (x <0) {
      return 0;
    }
    // Comment
-   else {
      return x;
-   }
  }

Fix #1383. noConfusingVoidType now accepts the void type in type parameter lists.

The rule no longer reports the following code:
```
f<void>();
```
Fix #728. useSingleVarDeclarator no longer outputs invalid code. Contributed by @Conaclos
Fix #1167. useValidAriaProps no longer reports aria-atomic as invalid. Contributed by @unvalley
Fix #1192. useTemplate now correctly handles parenthesized expressions and respects type coercions. Contributed by @n-gude

These cases are now properly handled:
```
"a" + (1 + 2) // `a${1 + 2}`
```
```
1 + (2 + "a") // `${1}${2}a`
```
Fix #1456. useTemplate now reports expressions with an interpolated template literal and non-string expressions. Contributed by @n-gude

The following code is now reported:
```
`a${1}` + 2;
```
Fix #1436. useArrowFunction now applies a correct fix when a function expression is used in a call expression or a member access. Contributed by @Conaclos

For example, the rule proposed the following fix:
```
- const called = function() {}();
+ const called = () => {}();
```
It now proposes a fix that adds the needed parentheses:
```
- const called = function() {}();
+ const called = (() => {})();
```
Fix #696. useHookAtTopLevel now correctly detects early returns before the calls to the hook.
The code fix of noUselessTypeCOnstraint now adds a trailing comma when needed to disambiguate a type parameter list from a JSX element. COntributed by @Conaclos
Fix #578. useExhaustiveDependencies now correctly recognizes hooks namespaced under the React namespace. Contributed by @XiNiHa
Fix #910. noSvgWithoutTitle now ignores <svg> element with aria-hidden="true". COntributed by @vasucp1207

Parser

BREAKING CHANGES

The representation of imports has been simplified. Contributed by @Conaclos

The new representation is closer to the ECMAScript standard. It provides a single way of representing a namespace import such as import * as ns from "". It rules out some invalid states that was previously representable. For example, it is no longer possible to represent a combined import with a type qualifier such as import type D, { N } from "".

See #1163 for more details.

New features

Imports and exports with both an import attribute and a type qualifier are now reported as parse errors.

import type A from "mod" with { type: "json" };
//     ^^^^              ^^^^^^^^^^^^^^^^^^^^^
//     parse error

Bug fixes

Fix #1077 where parenthesized identifiers in conditional expression were being parsed as arrow expressions. Contributed by @kalleep

These cases are now properly parsed:

JavaScript:
```
  a ? (b) : a => {};
```
TypeScript:
```
  a ? (b) : a => {};
```
JSX:
```
  bar ? (foo) : (<a>{() => {}}</a>);
```
Allow empty type parameter lists for interfaces and type aliases (#1237). COntributed by @togami2864

TypeScript allows interface declarations and type aliases to have empty type parameter lists. Previously Biome didn't handle this edge case. Now, it correctly parses this syntax:
```
interface Foo<> {}
type Bar<> = {};
```

Crates

BREAKING CHANGES

Rename the biome_js_unicode_table crate to biome_unicode_table (#1302). COntributed by @chansuke

1.4.1 (2023-11-30)

Editors

Bug fixes

Fix #933. Some files are properly ignored in the LSP too. E.g. package.json, tsconfig.json, etc.
Fix #1394, by inferring the language extension from the internal saved files. Now newly created files JavaScript correctly show diagnostics.

Formatter

Bug fixes

Fix some accidental line breaks when printing array expressions within arrow functions and other long lines #917. Contributed by @faultyserver
Match Prettier's breaking strategy for ArrowChain layouts #934. Contributed by @faultyserver
Fix double-printing of leading comments in arrow chain expressions #951. Contributed by @faultyserver

Linter

Bug fixes

Fix #910, where the rule noSvgWithoutTitle should skip elements that have aria-hidden attributes. Contributed by @vasucp1207

New features

Add useForOf rule. The rule recommends a for-of loop when the loop index is only used to read from an array that is being iterated. Contributed by @victor-teles

Enhancement

Address #924 and #920. noUselessElse now ignores else clauses that follow at least one if statement that doesn't break early. Contributed by @Conaclos

For example, the following code is no longer reported by the rule:

function f(x) {
    if (x < 0) {
      // this `if` doesn't break early.
    } else if (x > 0) {
        return x;
    } else {
        // This `else` block was previously reported as useless.
    }
}

Bug fixes

Fix #918. useSimpleNumberKeys no longer repports false positive on comments. Contributed by @kalleep
Fix #953. noRedeclare no longer reports type parameters with the same name in different mapped types as redeclarations. Contributed by @Conaclos
Fix #608. useExhaustiveDependencies no longer repports missing dependencies for React hooks without dependency array. Contributed by @kalleep

Parser

1.4.0 (2023-11-27)

CLI

Remove the CLI options from the lsp-proxy, as they were never meant to be passed to that command. Contributed by @ematipico
Add option --config-path to lsp-proxy and start commands. It's now possible to tell the Daemon server to load biome.json from a custom path. Contributed by @ematipico
Add option --diagnostic-level. It lets users control the level of diagnostics printed by the CLI. Possible values are: "info", "warn", and "hint". Contributed by @simonxabris
Add option --line-feed to the format command. Contributed by @SuperchupuDev
Add option --bracket-same-line to the format command. Contributed by @faultyserve
Add option --bracket-spacing to the format command. Contributed by @faultyserve

Bug fixes

Fix the command format, now it returns a non-zero exit code when if there pending diffs. Contributed by @ematipico

Formatter

New features

Add the configuration formatter.lineFeed. It allows changing the type of line endings. Contributed by @SuperchupuDev
Add the configuration javascript.formatter.bracketSameLine. It allows controlling whether ending > of a multi-line JSX element should be on the last attribute line or not. #627. Contributed by @faultyserver
Add the configuration javascript.formatter.bracketSpacing. It allows controlling whether spaces are inserted around the brackets of object literals. #627. Contributed by @faultyserver

Bug fixes

Fix #832, the formatter no longer keeps an unnecessary trailing comma in type parameter lists. Contributed by @Conaclos
```
- class A<T,> {}
+ class A<T> {}
```
Fix #301, the formatter should not break before the in keyword. Contributed by @ematipico

Linter

Promoted rules

a11y/noInteractiveElementToNoninteractiveRole
complexity/noThisInStatic
complexity/useArrowFunction
correctness/noEmptyCharacterClassInRegex
correctness/noInvalidNewBuiltin
style/noUselessElse
style/useAsConstAssertion
style/useShorthandAssign
suspicious/noApproximativeNumericConstant
suspicious/noMisleadingInstantiator
suspicious/noMisrefactoredShorthandAssign

The following rules are now recommended:

a11y/noAccessKey
a11y/useHeadingContent
complexity/useSimpleNumberKeys

The following rules are now deprecated:

correctness/noNewSymbol The rule is replaced by correctness/noInvalidNewBuiltin

New features

Add noDefaultExport which disallows export default. Contributed by @Conaclos
Add noAriaHiddenOnFocusable which reports hidden and focusable elements. Contributed by @vasucp1207
Add noImplicitAnyLet that reports variables declared with let and without initialization and type annotation. Contributed by @TaKO8Ki and @b4s36t4
Add useAwait that reports async functions that don't use an await expression.
Add useValidAriaRole. Contributed by @vasucp1207
Add useRegexLiterals that suggests turning call to the regex constructor into regex literals. COntributed by @Yuiki

Enhancements

Add an unsafe code fix for a11y/useAriaActivedescendantWithTabindex

Bug fixes

Fix #639 by ignoring unused TypeScript's mapped key. Contributed by @Conaclos
Fix #565 by handling several infer with the same name in extends clauses of TypeScript's conditional types. Contributed by @Conaclos
Fix #653. noUnusedImports now correctly removes the entire line where the unused import is. Contributed by @Conaclos
Fix #607 useExhaustiveDependencies, ignore optional chaining, Contributed by @msdlisper
Fix #676, by using the correct node for the "noreferrer" when applying the code action. Contributed by @ematipico
Fix #455. The CLI can now print complex emojis to the console correctly.
Fix #727. noInferrableTypes now correctly keeps type annotations when the initialization expression is null. Contributed by @Conaclos
Fix #784, noSvgWithoutTitle fixes false-positives to aria-label and reports svg's role attribute is implicit. Contributed by @unvalley
Fix #834 that made noUselessLoneBlockStatements reports block statements of switch clauses. Contributed by @vasucp1207
Fix #783 that made noUselessLoneBlockStatements reports block statements of try-catch structures. Contributed by @hougesen
Fix #69 that made correctness/noUnnecessaryContinue incorrectly reports a continue used to break a switch clause. Contributed by @TaKO8Ki
Fix #664 by improving the diagnostic of style/useNamingConvention when double capital are detected in strict camel case mode. Contributed by @vasucp1207
Fix #643 that erroneously parsed the option of complexity/useExhaustiveDependencies. Contributed by @arendjr

Parser

Bug fixes

Fix #846 that erroneously parsed <const T,>() => {} as a JSX tag instead of an arrow function when both TypeScript and JSX are enabled.

VSCode

1.3.3 (2023-10-31)

Analyzer

Bug fixes

Fix #604 which made noConfusingVoidType report false positives when the void type is used in a generic type parameter. Contributed by @unvalley

CLI

Bug fixes

Fix how overrides behave. Now ignore and include apply or not the override pattern, so they override each other. Now the options inside overrides override the top-level options.
Bootstrap the logger only when needed. Contributed by @ematipico
Fix how overrides are run. The properties ignore and include have different semantics and only apply/not apply an override. Contributed by @ematipico

Editors

Bug fixes

Fix #592, by changing binary resolution in the IntelliJ plugin. Contributed by @Joshuabaker2

Formatter

Bug fixes

Apply the correct layout when the right hand of an assignment expression is an await expression or a yield expression. Contributed by @ematipico
Fix #303, where nested arrow functions didn't break. Contributed by @victor-teles

Linter

New features

Add noUnusedPrivateClassMembers rule. The rule disallow unused private class members. Contributed by @victor-teles

Bug fixes

Fix #175 which made noRedeclare report index signatures using the name of a variable in the parent scope.
Fix #557 which made noUnusedImports report imported types used in typeof expression. Contributed by @Conaclos
Fix #576 by removing some erroneous logic in noSelfAssign. Contributed by @ematipico
Fix #861 that made noUnusedVariables always reports the parameter of a non-parenthesize arrow function as unused.
Fix #595 by updating unsafe-apply logic to avoid unexpected errors in noUselessFragments. Contributed by @nissy-dev
Fix #591 which made noRedeclare report type parameters with identical names but in different method signatures. Contributed by @Conaclos
Support more a11y roles and fix some methods for a11y lint rules Contributed @nissy-dev
Fix #609 useExhaustiveDependencies, by removing useContext, useId and useSyncExternalStore from the known hooks. Contributed by @msdlisper
Fix useExhaustiveDependencies, by removing useContext, useId and useSyncExternalStore from the known hooks. Contributed by @msdlisper
Fix #871 and #610. Now useHookAtTopLevel correctly handles nested functions. Contributed by @arendjr

The options of the rule useHookAtTopLevel are deprecated and will be removed in Biome 2.0. The rule now determines the hooks using the naming convention set by React.

{
  "linter": {
    "rules": {
      "correctness": {
+        "useHookAtTopLevel": "error",
-        "useHookAtTopLevel": {
-          "level": "error",
-          "options": {
-            "hooks": [
-              {
-                "name": "useLocation",
-                "closureIndex": 0,
-                "dependenciesIndex": 1
-              },
-              { "name": "useQuery", "closureIndex": 1, "dependenciesIndex": 0 }
-            ]
-          }
-        }
      }
    }
  }
}

Parser

Enhancements

Support RegExp v flag. Contributed by @nissy-dev
Improve error messages. Contributed by @ematipico

1.3.1 (2023-10-20)

CLI

Bug fixes

Fix rage command, now it doesn't print info about running servers. Contributed by @ematipico

Editors

Bug fixes

Fix #552, where the formatter isn't correctly triggered in Windows systems. Contributed by @victor-teles

Linter

New features

Add noThisInStatic rule. Contributed by @ditorodev and @Conaclos

Bug fixes

Fix #548 which made noSelfAssign panic.
Fix #555, by correctly map globals into the workspace.

1.3.0 (2023-10-19)

Analyzer

Enhancements

Import sorting is safe to apply now, and it will be applied when running check --apply instead of check --apply-unsafe.
Import sorting now handles Bun imports bun:<name>, absolute path imports /<path>, and Node's subpath imports #<name>. See our documentation for more details. Contributed by @Conaclos

CLI

Bug fixes

Fix #319. The command biome lint now shows the correct options. Contributed by @ematipico
Fix #312. Running biome --version now exits with status code 0 instead of 1. Contributed by @nhedger
Fix a bug where the extends functionality doesn't carry over organizeImports.ignore. Contributed by @ematipico
The CLI now returns the original content when using stdin and the original content doesn't change. Contributed by @ematipico

New features

Add support for BIOME_BINARY environment variable to override the location of the binary. Contributed by @ematipico
Add option --indent-width, and deprecated the option --indent-size. Contributed by @ematipico
Add option --javascript-formatter-indent-width, and deprecated the option --javascript-formatter-indent-size. Contributed by @ematipico
Add option --json-formatter-indent-width, and deprecated the option --json-formatter-indent-size. Contributed by @ematipico
Add option --daemon-logs to biome rage. The option is required to view Biome daemon server logs. Contributed by @unvalley

Add support for logging. By default, Biome doesn't log anything other than diagnostics. Logging can be enabled with the new option --log-level:

biome format --log-level=info ./src

There are four different levels of logging, from the most verbose to the least verbose: debug, info, warn and error. Here's how an INFO log will look like:

2023-10-05T08:27:01.954727Z  INFO  Analyze file ./website/src/playground/components/Resizable.tsx
  at crates/biome_service/src/file_handlers/javascript.rs:298 on biome::worker_5
  in Pulling diagnostics with categories: RuleCategories(SYNTAX)
  in Processes formatting with path: "./website/src/playground/components/Resizable.tsx"
  in Process check with path: "./website/src/playground/components/Resizable.tsx"

You can customize how the log will look like with a new option --log-kind. The supported kinds are: pretty, compact and json.

pretty is the default logging. Here's how a compact log will look like:

2023-10-05T08:29:04.864247Z  INFO biome::worker_2 Process check:Processes linting:Pulling diagnostics: crates/biome_service/src/file_handlers/javascript.rs: Analyze file ./website/src/playground/components/Resizable.tsx path="./website/src/playground/components/Resizable.tsx" path="./website/src/playground/components/Resizable.tsx" categories=RuleCategories(LINT)
2023-10-05T08:29:04.864290Z  INFO biome::worker_7 Process check:Processes formatting: crates/biome_service/src/file_handlers/javascript.rs: Format file ./website/src/playground/components/Tabs.tsx path="./website/src/playground/components/Tabs.tsx" path="./website/src/playground/components/Tabs.tsx"
2023-10-05T08:29:04.879332Z  INFO biome::worker_2 Process check:Processes formatting:Pulling diagnostics: crates/biome_service/src/file_handlers/javascript.rs: Analyze file ./website/src/playground/components/Resizable.tsx path="./website/src/playground/components/Resizable.tsx" path="./website/src/playground/components/Resizable.tsx" categories=RuleCategories(SYNTAX)
2023-10-05T08:29:04.879383Z  INFO biome::worker_2 Process check:Processes formatting: crates/biome_service/src/file_handlers/javascript.rs: Format file ./website/src/playground/components/Resizable.tsx path="./website/src/playground/components/Resizable.tsx" path="./website/src/playground/components/Resizable.tsx"

Enhancements

Deprecated the environment variable ROME_BINARY. Use BIOME_BINARY instead. Contributed by @ematipico
Biome doesn't check anymore the presence of the .git folder when VCS support is enabled. Contributed by @ematipico
biome rage doesn't print the logs of the daemon, use biome rage --daemon-logs to print them. Contributed by @unvalley

Configuration

New features

Add option formatter.indentWidth, and deprecated the option formatter.indentSize. Contributed by @ematipico
Add option javascript.formatter.indentWidth, and deprecated the option javascript.formatter.indentSize. Contributed by @ematipico
Add option json.formatter.indentWidth, and deprecated the option json.formatter.indentSize. Contributed by @ematipico
Add option include to multiple sections of the configuration
- files.include;
- formatter.include;
- linter.include;
- organizeImports.include; When include and ignore are both specified, ignore takes precedence over include

Add option overrides, where users can modify the behaviour of the tools for certain files or paths.

For example, it's possible to modify the formatter lineWidth, and even quoteStyle for certain files that are included in glob path generated/**:

{
  "formatter": {
    "lineWidth": 100
  },
  "overrides": [
    {
      "include": ["generated/**"],
      "formatter": {
        "lineWidth": 160
      },
      "javascript": {
        "formatter": {
          "quoteStyle": "single"
        }
      }
    }
  ]
}

Or, you can disable certain rules for certain path, and disable the linter for other paths:

{
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true
    }
  },
  "overrides": [
    {
      "include": ["lib/**"],
      "linter": {
        "rules": {
          "suspicious": {
            "noDebugger": "off"
          }
        }
      }
    },
    {
      "include": ["shims/**"],
      "linter": {
        "enabled": false
      }
    }
  ]
}

Bug fixes

Fix #343, extends was incorrectly applied to the biome.json file. Contributed by @ematipico

Editors

Bug fixes

Fix #404. Biome intellij plugin now works on Windows. Contributed by @victor-teles
Fix #402. Biome format on intellij plugin now recognize biome.json. Contributed by @victor-teles

Formatter

Enhancements

Use OnceCell for the Memoized memory because that's what the RefCell<Option> implemented. Contributed by @denbezrukov

Linter

Promoted rules

complexity/noExcessiveCognitiveComplexity
complexity/noVoid
correctness/useExhaustiveDependencies
correctness/useHookAtTopLevel
performance/noAccumulatingSpread
style/useCollapsedElseIf
suspicious/noConfusingVoidType
suspicious/noFallthroughSwitchClause
suspicious/noGlobalIsFinite
suspicious/noGlobalIsNan
suspicious/useIsArray

The following rules are now recommended:

noAccumulatingSpread
noConfusingVoidType
noFallthroughSwitchClause
noForEach

New features

Add noEmptyCharacterClassInRegex rule. The rule reports empty character classes and empty negated character classes in regular expression literals. Contributed by @Conaclos
Add noMisleadingInstantiator rule. The rule reports the misleading use of the new and constructor methods. Contributed by @unvalley
Add noUselessElse rule. The rule reports else clauses that can be omitted because their if branches break. Contributed by @Conaclos
Add noUnusedImports rule. The rule reports unused imports and suggests removing them. Contributed by @Conaclos

noUnusedVariables reports also unused imports, but don't suggest their removal. Once noUnusedImports stabilized, noUnusedVariables will not report unused imports.
Add useShorthandAssign rule. The rule enforce use of shorthand operators that combine variable assignment and some simple mathematical operations. For example, x = x + 4 can be shortened to x += 4. Contributed by @victor-teles
Add useAsConstAssertion rule. The rule enforce use of as const assertion to infer literal types. Contributed by @unvalley
Add noMisrefactoredShorthandAssign rule. The rule reports shorthand assigns when variable appears on both sides. For example x += x + b Contributed by @victor-teles
Add noApproximativeNumericConstant rule. Contributed by @nikeee
Add noInteractiveElementToNoninteractiveRole rule. The rule enforces the non-interactive ARIA roles are not assigned to interactive HTML elements. Contributed by @nissy-dev
Add useAriaActivedescendantWithTabindex rule. The rule enforces that tabIndex is assigned to non-interactive HTML elements with aria-activedescendant. Contributed by @nissy-dev
Add noUselessLoneBlockStatements rule. The rule reports standalone blocks that don't include any lexical scoped declaration. Contributed by @emab
Add noInvalidNewBuiltin rule. The rule reports use of new on Symbol and BigInt. Contributed by @lucasweng

Enhancements

The following rules have now safe code fixes:
noAccumulatingSpread makes more check in order to reduce potential false positives. Contributed by @Vivalldi
noConstAssign now provides an unsafe code fix that replaces const with let. Contributed by @vasucp1207
noExcessiveComplexity default complexity threshold is now 15. Contributed by @arendjr
noPositiveTabindexValue now provides an unsafe code fix that set to 0 the tab index. Contributed by @vasucp1207
noUnusedLabels no longer reports unbreakable labeled statements. Contributed by @Conaclos
noUnusedVariables now reports unused TypeScript's type parameters. Contributed by @Conaclos
useAnchorContent now provides an unsafe code fix that removes the `aria-hidden`` attribute. Contributed by @vasucp1207
useValidAriaProps now provides an unsafe code fix that removes invalid properties. Contributed by @vasucp1207
noExcessiveComplexity was renamed to noExcessiveCognitiveComplexity

Bug fixes

Fix #294. noConfusingVoidType no longer reports false positives for return types. Contributed by @b4s36t4
Fix #313. noRedundantUseStrict now keeps leading comments.
Fix #383. noMultipleSpacesInRegularExpressionLiterals now provides correct code fixes when consecutive spaces are followed by a quantifier. Contributed by @Conaclos
Fix #397. useNumericLiterals now provides correct code fixes for signed numbers. Contributed by @Conaclos
Fix 452. The linter panicked when it met a malformed regex (a regex not ending with a slash).
Fix #104. We now correctly handle types and values with the same name.
Fix #243 a false positive case where the incorrect scope was defined for the infer type in rule noUndeclaredVariables. Contributed by @denbezrukov
Fix #322, now noSelfAssign correctly handles literals inside call expressions.
Changed how noSelfAssign behaves. The rule is not triggered anymore on function calls. Contributed by @ematipico

Parser

Enhance diagnostic for infer type handling in the parser. The 'infer' keyword can only be utilized within the 'extends' clause of a conditional type. Using it outside this context will result in an error. Ensure that any type declarations using 'infer' are correctly placed within the conditional type structure to avoid parsing issues. Contributed by @denbezrukov

Add support for parsing trailing commas inside JSON files:

{
  "json": {
    "parser": {
      "allowTrailingCommas": true
    }
  }
}

Contributed by @nissy-dev

VSCode

1.2.2 (2023-09-16)

CLI

Bug fixes

Fix a condition where import sorting wasn't applied when running biome check --apply

1.2.1 (2023-09-15)

Configuration

Fix an edge case where the formatter language configuration wasn't picked.
Fix the configuration schema, where json.formatter properties weren't transformed in camel case.

1.2.0 (2023-09-15)

CLI

New features

Add new options to customize the behaviour the formatter based on the language of the file
- --json-formatter-enabled
- --json-formatter-indent-style
- --json-formatter-indent-size
- --json-formatter-line-width
- --javascript-formatter-enabled
- --javascript-formatter-indent-style
- --javascript-formatter-indent-size
- --javascript-formatter-line-width

Bug fixes

Fix a bug where --errors-on-warning didn't work when running biome ci command.

Configuration

New features

Add new options to customize the behaviour of the formatter based on the language of the file
- json.formatter.enabled
- json.formatter.indentStyle
- json.formatter.indentSize
- json.formatter.lineWidth
- javascript.formatter.enabled
- javascript.formatter.indentStyle
- javascript.formatter.indentSize
- javascript.formatter.lineWidth

Linter

Promoted rules

New rules are incubated in the nursery group. Once stable, we promote them to a stable group. The following rules are promoted:

a11y/noAriaUnsupportedElements
a11y/noNoninteractiveTabindex
a11y/noRedundantRoles
a11y/useValidAriaValues
complexity/noBannedTypes
complexity/noStaticOnlyClass
complexity/noUselessEmptyExport
complexity/noUselessThisAlias
correctness/noConstantCondition
correctness/noNonoctalDecimalEscape
correctness/noSelfAssign
style/useLiteralEnumMembers
style/useNamingConvention
suspicious/noControlCharactersInRegex
suspicious/noUnsafeDeclarationMerging
suspicious/useGetterReturn

New rules

Add noConfusingVoidType rule. The rule reports the unusual use of the void type. Contributed by @shulandmimi

Removed rules

Remove noConfusingArrow

Code formatters, such as prettier and Biome, always adds parentheses around the parameter or the body of an arrow function. This makes the rule useless.

Contributed by @Conaclos

Enhancements

noFallthroughSwitchClause now relies on control flow analysis to report most of the switch clause fallthrough. Contributed by @Conaclos
noAssignInExpressions no longer suggest code fixes. Most of the time the suggestion didn't match users' expectations. Contributed by @Conaclos
noUselessConstructor no longer emits safe code fixes. Contributed by @Conaclos

All code fixes are now emitted as unsafe code fixes. Removing a constructor can change the behavior of a program.
useCollapsedElseIf now only provides safe code fixes. Contributed by @Conaclos
noUnusedVariables now reports more cases.

The rule is now able to ignore self-writes. For example, the rule reports the following unused variable:
```
let a = 0;
a++;
a += 1;
```
The rule is also capable of detecting an unused declaration that uses itself. For example, the rule reports the following unused interface:
```
interface I {
  instance(): I
}
```
Finally, the rule now ignores all TypeScript declaration files, including global declaration files.

Contributed by @Conaclos

Bug fixes

Fix #182, making useLiteralKeys retains optional chaining. Contributed by @denbezrukov
Fix #168, fix useExhaustiveDependencies false positive case when stable hook is on a new line. Contributed by @denbezrukov

Fix #137, fix noRedeclare false positive case with TypeScript module declaration:

declare module '*.gif' {
    const src: string;
}

declare module '*.bmp' {
    const src: string;
}

Contributed by @denbezrukov

Fix #258, fix noUselessFragments the case where the rule removing an assignment. Contributed by @denbezrukov
Fix #266, where complexity/useLiteralKeys emitted a code action with an invalid AST. Contributed by @ematipico
Fix #105, removing false positives reported by noUnusedVariables.

The rule no longer reports the following used variable:
```
const a = f(() => a);
```
Contributed by @Conaclos

VSCode

Enhancements

Improve server binary resolution when using certain package managers, notably pnpm.

The new strategy is to point to node_modules/.bin/biome path, which is consistent for all package managers.

1.1.2 (2023-09-07)

Editors

Bug fixes

Fix a case where an empty JSON file would cause the LSP server to crash. Contributed by @ematipico

Linter

Enhancements

useNamingConvention now accepts import namespaces in PascalCase and rejects export namespaces in CONSTANT_CASE.

The following code is now valid:
```
import * as React from "react";
```
And the following code is now invalid:
```
export * as MY_NAMESPACE from "./lib.js";
```
Contributed by @Conaclos
noUselessConstructor now ignores decorated classes and decorated parameters. The rule now gives suggestions instead of safe fixes when parameters are annotated with types. Contributed by @Conaclos

1.1.1 (2023-09-07)

Analyzer

Bug fixes

The diagnostic for // rome-ignore suppression comment should not be a warning. A warning could block the CI, marking a gradual migration difficult. The code action that changes // rome-ignore to // biome-ignore is disabled as consequence. Contributed by @ematipico

1.1.0 (2023-09-06)

Analyzer

Enhancements

Add a code action to replace rome-ignore with biome-ignore. Use biome check --apply-unsafe to update all the comments. The action is not bulletproof, and it might generate unwanted code, that's why it's unsafe action. Contributed by @ematipico

CLI

Enhancements

Biome now reports a diagnostics when a rome.json file is found.
biome migrate --write creates biome.json from rome.json, but it won't delete the rome.json file. Contributed by @ematipico

Bug fixes

Biome uses biome.json first, then it attempts to use rome.json.
Fix a case where Biome couldn't compute correctly the ignored files when the VSC integration is enabled. Contributed by @ematipico

Configuration

Editors

Bug fixes

The LSP now uses its own socket and won't rely on Biome's socket. This fixes some cases where users were seeing multiple servers in the rage output.

Formatter

Enhancements

You can use // biome-ignore as suppression comment.
The // rome-ignore suppression is deprecated.

JavaScript APIs

Linter

New features

Add useCollapsedElseIf rule. This new rule requires merging an else and an if, if the if statement is the only statement in the else block. Contributed by @n-gude

Enhancements

useTemplate now reports all string concatenations.

Previously, the rule ignored concatenation of a value and a newline or a backquote. For example, the following concatenation was not reported:
```
v + "\n";
"`" + v + "`";
```
The rule now reports these cases and suggests the following code fixes:
```
- v + "\n";
+ `${v}\n`;
- v + "`";
+ `\`${v}\``;
```
Contributed by @Conaclos
useExponentiationOperator suggests better code fixes.

The rule now preserves any comment preceding the exponent, and it preserves any parenthesis around the base or the exponent. It also adds spaces around the exponentiation operator **, and always adds parentheses for pre- and post-updates.
```
- Math.pow(a++, /**/ (2))
+ (a++) ** /**/ (2)
```
Contributed by @Conaclos
You can use // biome-ignore as suppression comment.
The // rome-ignore suppression is deprecated.

Bug fixes

Fix #80, making noDuplicateJsxProps case-insensitive.

Some frameworks, such as Material UI, rely on the case-sensitivity of JSX properties. For example, TextField has two properties with the same name, but distinct cases:
```
<TextField inputLabelProps="" InputLabelProps=""></TextField>
```
Contributed by @Conaclos
Fix #138

noCommaOperator now correctly ignores all use of comma operators inside the update part of a for loop. The following code is now correctly ignored:
```
for (
  let i = 0, j = 1, k = 2;
  i < 100;
  i++, j++, k++
) {}
```
Contributed by @Conaclos
Fix rome#4713.

Previously, useTemplate made the following suggestion:
```
- a + b + "px"
+ `${a}${b}px`
```
This breaks code where a and b are numbers.

Now, the rule makes the following suggestion:
```
- a + b + "px"
+ `${a + b}px`
```
Contributed by @Conaclos

Fix rome#4109

Previously, useTemplate suggested an invalid code fix when a leading or trailing single-line comment was present:

  // leading comment
- 1 /* inner comment */ + "+" + 2 // trailing comment
+ `${// leading comment
+ 1 /* inner comment */}+${2 //trailing comment}` // trailing comment

Now, the rule correctly handles this case:

  // leading comment
- 1 + "+" + 2 // trailing comment
+ `${1}+${2}` // trailing comment

As a sideeffect, the rule also suggests the removal of any inner comments.

Contributed by @Conaclos

Fix rome#3850

Previously useExponentiationOperator suggested invalid code in a specific edge case:
```
- 1 +Math.pow(++a, 2)
+ 1 +++a**2
```
Now, the rule properly adds parentheses:
```
- 1 +Math.pow(++a, 2)
+ 1 +(++a) ** 2
```
Contributed by @Conaclos
Fix #106

noUndeclaredVariables now correctly recognizes some TypeScript types such as Uppercase.

Contributed by @Conaclos
Fix rome#4616

Previously noUnreachableSuper reported valid codes with complex nesting of control flow structures.

Contributed by @Conaclos

1.0.0 (2023-08-28)

Analyzer

BREAKING CHANGES

The organize imports feature now groups import statements by "distance".

Modules "farther" from the user are put on the top, and modules "closer" to the user are placed on the bottom. Check the documentation for more information about it.
The organize imports tool is enabled by default. If you don't want to use it, you need to disable it explicitly:
```
{
  "organizeImports": {
    "enabled": false
  }
}
```

CLI

BREAKING CHANGES

The CLI now exists with an error when there's an error inside the configuration.

Previously, biome would raise warnings and continue the execution by applying its defaults.

This could have been better for users because this could have created false positives in linting or formatted code with a configuration that wasn't the user's.
The command biome check now shows formatter diagnostics when checking the code.

The diagnostics presence will result in an error code when the command finishes.

This aligns with semantic and behaviour meant for the command biome check.
init command emits a biome.json file;

Other changes

Fix #4670, don't crash at empty default export.
Fix #4556, which correctly handles new lines in the .gitignore file across OS.
Add a new option to ignore unknown files --files-ignore-unknown:
```
biome format --files-ignore-unknown ./src
```
Doing so, Biome won't emit diagnostics for files that doesn't know how to handle.
Add the new option --no-errors-on-unmatched:
```
biome format --no-errors-on-unmatched ./src
```
Biome doesn't exit with an error code if no files were processed in the given paths.
Fix the diagnostics emitted when running the biome format command.
Biome no longer warns when discovering (possibly infinite) symbolic links between directories.

This fixes #4193 which resulted in incorrect warnings when a single file or directory was pointed at by multiple symbolic links. Symbolic links to other symbolic links do still trigger warnings if they are too deeply nested.
Introduced a new command called biome lint, which will only run lint rules against the code base.
Biome recognizes known files as "JSON files with comments allowed":
- typescript.json;
- tsconfig.json;
- jsconfig.json;
- tslint.json;
- babel.config.json;
- .babelrc.json;
- .ember-cli;
- typedoc.json;
- .eslintrc.json;
- .eslintrc;
- .jsfmtrc;
- .jshintrc;
- .swcrc;
- .hintrc;
- .babelrc;
Add support for biome.json;

Configuration

Other changes

Add a new option to ignore unknown files:
```
{
   "files": {
      "ignoreUnknown": true
   }
}
```
Doing so, Biome won't emit diagnostics for file that it doesn't know how to handle.

Add a new "javascript" option to support the unsafe/experimental parameter decorators:

{
   "javascript": {
      "parser": {
         "unsafeParameterDecoratorsEnabled": true
      }
   }
}

Add a new "extends" option, useful to split the configuration file in multiple files:
```
{
  "extends": ["../sharedFormatter.json", "linter.json"]
}
```
The resolution of the files is file system based, Biome doesn't know how to resolve dependencies yet.
The commands biome check and biome lint now show the remaining diagnostics even when --apply-safe or --apply-unsafe are passed.
Fix the commands biome check and biome lint, they won't exit with an error code if no error diagnostics are emitted.
Add a new option --error-on-warnings, which instructs Biome to exit with an error code when warnings are emitted.
```
biome check --error-on-wanrings ./src
```

Add a configuration to enable parsing comments inside JSON files:

{
  "json": {
    "parser": {
      "allowComments": true
    }
  }
}

Editors

Other changes

The Biome LSP can now show diagnostics belonging to JSON lint rules.
The Biome LSP no longer applies unsafe quickfixes on-save when editor.codeActionsOnSave.quickfix.biome is enabled.
Fix #4564; files too large don't emit errors.
The Biome LSP sends client messages when files are ignored or too big.

Formatter

Add a new option called --jsx-quote-style.

This option lets you choose between single and double quotes for JSX attributes.
Add the option --arrow-parentheses.

This option allows setting the parentheses style for arrow functions.
The JSON formatter can now format .json files with comments.

Linter

Removed rules

Remove complexity/noExtraSemicolon (#4553)

The Biome formatter takes care of removing extra semicolons. Thus, there is no need for this rule.
Remove useCamelCase

Use useNamingConvention instead.

New rules

Add noExcessiveComplexity
Add useImportRestrictions
Add noFallthroughSwitchClause
Add noGlobalIsFinite

This rule recommends using Number.isFinite instead of the global and unsafe isFinite that attempts a type coercion.
Add noGlobalIsNan

This rule recommends using Number.isNaN instead of the global and unsafe isNaN that attempts a type coercion.
Add noUnsafeDeclarationMerging

This rule disallows declaration merging between an interface and a class.
Add noUselessThisAlias

This rule disallows useless aliasing of this in arrow functions.
Add useArrowFunction

This rule proposes turning function expressions into arrow functions. Function expressions that use this are ignored.
Add noDuplicateJsonKeys

This rule disallow duplicate keys in a JSON object.
Add noVoid

This rule disallows the use of void.
Add noNonoctalDecimalEscape

This rule disallows \8 and \9 escape sequences in string literals.
Add noUselessEmptyExport

This rule disallows useless export {}.
Add useIsArray

This rule proposes using Array.isArray() instead of instanceof Array.
Add useGetterReturn

This rule enforces the presence of non-empty return statements in getters. This makes the following code incorrect:
```
class Person {
    get firstName() {}
}
```

Promoted rules

New rules are promoted, please check #4750 for more details:

a11y/useHeadingContent
complexity/noForEach
complexity/useLiteralKeys
complexity/useSimpleNumberKeys
correctness/useIsNan
suspicious/noConsoleLog
suspicious/noDuplicateJsxProps

The following rules are now recommended:

**- noUselessFragments

noRedundantUseStrict
useExponentiationOperator**

Other changes

Add new TypeScript globals (AsyncDisposable, Awaited, DecoratorContext, and others) 4643.
noRedeclare: allow redeclare of index signatures are in different type members #4478
Improve noConsoleLog, noGlobalObjectCalls, useIsNan, and useNumericLiterals by handling globalThis and window namespaces.

For instance, the following code is now reported by noConsoleLog:
```
globalThis.console.log("log")
```
Improve noDuplicateParameters to manage constructor parameters.
Improve noInnerDeclarations

Now, the rule doesn't report false-positives about ambient TypeScript declarations. For example, the following code is no longer reported by the rule:
```
declare var foo;
```
Improve useEnumInitializers

The rule now reports all uninitialized members of an enum in a single diagnostic.

Moreover, ambient enum declarations are now ignored. This avoids reporting ambient enum declarations in TypeScript declaration files.
```
declare enum Weather {
  Rainy,
  Sunny,
}
```
Relax noBannedTypes and improve documentation

The rule no longer reports a user type that reuses a banned type name. The following code is now allowed:
```
import { Number } from "a-lib";
declare const v: Number;
```
The rule now allows the use of the type {} to denote a non-nullable generic type:
```
function f<T extends {}>(x: T) {
    assert(x != null);
}
```
And in a type intersection for narrowing a type to its non-nullable equivalent type:
```
type NonNullableMyType = MyType & {};
```
Improve noConstantCondition

The rule now allows while(true). This recognizes a common pattern in the web community:
```
while (true) {
  if (cond) {
    break;
  }
}
```
Improve the diagnostic and the code action of useDefaultParameterLast.

The diagnostic now reports the last required parameter which should precede optional and default parameters.

The code action now removes any whitespace between the parameter name and its initialization.
Relax noConfusingArrow

All arrow functions that enclose its parameter with parenthesis are allowed. Thus, the following snippet no longer trigger the rule:
```
var x = (a) => 1 ? 2 : 3;
```
The following snippet still triggers the rule:
```
var x = a => 1 ? 2 : 3;
```
Relax useLiteralEnumMembers

Enum members that refer to previous enum members are now allowed. This allows a common pattern in enum flags like in the following example:
```
enum FileAccess {
  None = 0,
  Read = 1,
  Write = 1 << 1,
  All = Read | Write,
}
```
Arbitrary numeric constant expressions are also allowed:
```
enum FileAccess {
  None = 0,
  Read = 2**0,
  Write = 2**1,
  All = Read | Write,
}
```
Improve useLiteralKeys.

Now, the rule suggests simplifying computed properties to string literal properties:
```
{
-  ["1+1"]: 2,
+  "1+1": 2,
}
```
It also suggests simplifying string literal properties to static properties:
```
{
-  "a": 0,
+  a: 0,
}
```
These suggestions are made in object literals, classes, interfaces, and object types.
Improve noNewSymbol.

The rule now handles cases where Symbol is namespaced with the global globalThis or window.

The rules useExhaustiveDependencies and useHookAtTopLevel accept a different shape of options

Old configuration:

{
  "linter": {
     "rules": {
        "nursery": {
           "useExhaustiveDependencies": {
              "level": "error",
              "options": {
                 "hooks": [
                    ["useMyEffect", 0, 1]
                 ]
              }
           }
        }
     }
  }
}

New configuration:

{
  "linter": {
     "rules": {
        "nursery": {
           "useExhaustiveDependencies": {
              "level": "error",
              "options": {
                 "hooks": [
                    {
                       "name": "useMyEffect",
                       "closureIndex": 0,
                       "dependenciesIndex": 1
                    }
                 ]
              }
           }
        }
     }
  }
}

noRedundantUseStrict check only 'use strict' directive to resolve false positive diagnostics.

React introduced new directives, "use client" and "use server". The rule raises false positive errors about these directives.
Fix a crash in the NoParameterAssign rule that occurred when there was a bogus binding. #4323
Fix useExhaustiveDependencies in the following cases #4330:
- when the first argument of hooks is a named function
- inside an export default function
- for React.use hooks
Fix noInvalidConstructorSuper that erroneously reported generic parents #4624.
Fix noDuplicateCase that erroneously reported as equals the strings literals "'" and '"' #4706.
Fix NoUnreachableSuper's false positive diagnostics (#4483) caused to nested if statement.

The rule no longer reports This constructor calls super() in a loop when using nested if statements in a constructor.
Fix useHookAtTopLevel's false positive diagnostics (#4637)

The rule no longer reports false positive diagnostics when accessing properties directly from a hook and calling a hook inside function arguments.
Fix noUselessConstructor which erroneously reported constructors with default parameters rome#4781
Fix noUselessFragments's panics when running biome check --apply-unsafe (#4637)

This rule's code action emits an invalid AST, so I fixed using JsxString instead of JsStringLiteral
Fix noUndeclaredVariables's false positive diagnostics (#4675)

The semantic analyzer no longer handles this reference identifier.
Fix noUnusedVariables's false positive diagnostics (#4688)

The semantic analyzer handles ts export declaration clause correctly.

Parser

Add support for decorators in class method parameters, example:

class AppController {
   get(@Param() id) {}
   // ^^^^^^^^ new supported syntax
}

This syntax is only supported via configuration, because it's a non-standard syntax.

{
   "javascript": {
      "parser": {
         "unsafeParameterDecoratorsEnabled": true
      }
   }
}

Add support for parsing comments inside JSON files:

{
  "json": {
    "parser": {
      "allowComments": true
    }
  }
}

Add support for the new using syntax
```
const using = resource.lock();
```

Files

CHANGELOG.md

Latest commit

History

CHANGELOG.md

File metadata and controls

Biome changelog

Unreleased

Analyzer

Bug fixed

CLI

New features

Bug fixes

Enhancements

Configuration

New features

Editors

Bug fixes

Formatter

New features

Bug fixes

JavaScript APIs

Linter

BREAKING CHANGES

New features

Enhancements

Bug fixes

Parser

Bug fixes

1.5.3 (2024-01-22)

LSP

Bug fixes

Configuration

Bug fixes

Formatter

Bug fixes

Linter

Bug fixes

Parser

Bug fixes

Website

New

Fixes

1.5.2 (2024-01-15)

CLI

Bug fixes

Configuration

Bug fixes

Formatter

Bug fixes

Linter

Enhancements

Bug fixes

1.5.1 (2024-01-10)

CLI

Bug fixes

Formatter

Bug fixes

Linter

Bug fixes

1.5.0 (2024-01-08)

Analyzer

CLI

New features

Bug fixes

Configuration

New features

Editors

New features

Formatter

Bug fixes

JavaScript APIs

Linter

Promoted rules

New features

Enhancements

Bug fixes

Parser

BREAKING CHANGES

New features