plugin-esm

@putout/plugin-esm

The static import statement is used to import read only live bindings which are exported by another module. The imported bindings are called live bindings because they are updated by the module that exported the binding, but cannot be re-assigned by the importing module.

(c) MDN

🐊Putout plugin adds ability to transform to new Node.js API and apply best practices.

Install

npm i putout @putout/plugin-esm -D

Rules

• ✅ declare-imports-first;
• ✅ group-imports-by-source;
• ✅ merge-duplicate-imports;
• ✅ remove-quotes-from-import-assertions;
• ✅ remove-empty-import;
• ✅ remove-empty-export;
• ✅ sort-imports-by-specifiers;

Config

{
    "rules": {
        "esm/declare-imports-first": "on",
        "esm/group-imports-by-source": "on",
        "esm/merge-duplicate-imports": "on",
        "esm/remove-quotes-from-import-assertions": "on",
        "esm/remove-empty-export": "on",
        "esm/remove-empty-import": ["on", {
            "ignore": []
        }],
        "esm/sort-imports-by-specifiers": "on"
    }
}

declare-imports-first

Check out in 🐊Putout Editor. For CommonJS use nodejs/declare-after-require.

❌ Example of incorrect code

const [arg] = process.argv;
import esbuild from 'esbuild';

✅ Example of correct code

import esbuild from 'esbuild';

const [arg] = process.argv;

group-imports-by-source

Group order:

• ✅ builtins;
• ✅ external;
• ✅ internal;

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import fs from 'node:fs';
import {lodash} from 'lodash';
import react from 'react';
import d from '../hello.js';
import ss from '../../bb/ss.js';
import b from './ss.js';

const c = 5;

✅ Example of correct code

import fs from 'node:fs';
import react from 'react';
import {lodash} from 'lodash';
import b from './ss.js';
import d from '../hello.js';
import ss from '../../bb/ss.js';

const c = 5;

merge-duplicate-imports

join

To disable use:

{
    "rules": {
        "esm/merge-duplicate-imports-join": "off"
    }
}

❌ Example of incorrect code

import test from 'supertape';
import {stub} from 'supertape';

✅ Example of correct code

import test, {stub} from 'supertape';

rename

Checkout in 🐊Putout Editor.

To disable use:

{
    "rules": {
        "esm/merge-duplicate-imports-rename": "off"
    }
}

❌ Example of incorrect code

import putout from './putout.js';
import all from './putout.js';
import x from './putout.js';

console.log(all);
console.log(x);

✅ Example of correct code

import putout from './putout.js';

console.log(putout);
console.log(putout);

remove-empty-export

-export {};

remove-empty-import

-import 'abc';

remove-quotes-from-import-assertions

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import json from './mod.json' with { type: 'json' };

✅ Example of correct code

import json from './mod.json' with { type: 'json' };

sort-imports-by-specifiers

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import {
    a,
    b,
    c,
    d,
} from 'd';
import a1 from 'a1';

✅ Example of correct code

import a1 from 'a1';
import {
    a,
    b,
    c,
    d,
} from 'd';

convert-assert-to-with

This feature would ideally use the with keyword to denote attributes, but there are existing implementations based on a previous version of the proposal using the assert keyword. Due to potential web compatibility risks, the proposal still includes assert marked as deprecated. Usage of the old syntax is discouraged, and its removal is being investigated.

(c) tc39

Check out in 🐊Putout Editor.

❌ Example of incorrect code

import json from './foo.json' assert { type: 'json' };

import('foo.json', {
    assert: {
        type: 'json',
    },
});

✅ Example of correct code

import json from './foo.json' with { type: 'json' };

import('foo.json', {
    with: {
        type: 'json',
    },
});

License

MIT