biome.jsonc

{
  "$schema": "./node_modules/@biomejs/biome/configuration_schema.json",
  "vcs": {
    "enabled": true,
    "clientKind": "git",
    "useIgnoreFile": true,
    "defaultBranch": "main"
  },
  "organizeImports": {
    "enabled": false
  },
  "formatter": {
    "enabled": true,
    "formatWithErrors": true,
    "indentStyle": "space",
    "indentWidth": 2,
    "lineEnding": "lf",
    "lineWidth": 120
  },
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true,
      "correctness": {
        // this rule is annoying during development (it can always be turned on in CI)
        "noUnusedImports": "off"
      },
      "style": {
        "noDefaultExport": "off",
        "noNonNullAssertion": { "level": "warn" },
        "useImportType": { "level": "error" }
      },
      "complexity": {
        // disable rule because arrow functions are in fact different vs. function syntax (e.g. they do not bind `this`)
        // react components lose the component name with arrow functions but do not with the function() syntax
        "useArrowFunction": { "fix": "none", "level": "off" }
      },
      "a11y": {
        // the majority of our svg icons are aria-hidden so this rule is not useful
        "noSvgWithoutTitle": {
          "level": "off"
        },
        // bs rule says to use semantic elements with native alert role but wtf element is that
        "useSemanticElements": {
          "level": "off"
        }
      },
      "suspicious": {
        // set to warn because key={index} is ok in react for trivial cases where components will not be reordered
        "noArrayIndexKey": { "level": "warn" }
      },
      "nursery": {}
    }
  },
  "javascript": {
    "formatter": {
      "enabled": true,
      "quoteStyle": "single",
      "trailingCommas": "all",
      "semicolons": "asNeeded",
      "jsxQuoteStyle": "double"
    }
  },
  "json": {
    "parser": {
      "allowComments": true,
      "allowTrailingCommas": false
    },
    "formatter": {
      "enabled": true
    }
  },
  "css": {
    "parser": {
      "allowWrongLineComments": false,
      "cssModules": false
    }
  },
  "overrides": [
    // computed keys are a common pattern with libraries such as clsx
    {
      "include": ["apps/**/*.tsx", "functions/**/*.ts", "packages/react-*/**"],
      "linter": {
        "rules": {
          "complexity": {
            "useLiteralKeys": "off"
          }

          // "nursery": {}
        }
      }
    },
    // false positive when putting routes in a tuple with a jsx component
    {
      "include": ["apps/**/router.tsx"],
      "linter": {
        "rules": {
          "correctness": {
            "useJsxKeyInIterable": "off"
          }
        }
      }
    },
    // loosen rules for tests to allow `any`
    {
      "include": ["**/*.test.ts", "**/*.test.tsx"],
      "linter": {
        "rules": {
          "complexity": {
            "noForEach": "off"
          },
          "correctness": {
            "noUnusedImports": "off"
          },
          "suspicious": {
            "noExplicitAny": "off"
          }
        }
      }
    }
  ],
  "files": {
    "ignore": [
      // pnpm and npm format package.json differently than biome so ignore to avoid unnecessary changes in git
      "package.json",

      // other patterns (also refer to .gitignore when `vcs.useIgnoreFile` is `true`)
      "**/node_modules",
      "**/migrations",
      "**/coverage",
      "**/storybook-static"
    ]
  }
}