azu/eslint-cjs-to-esm

ESLint wrapper for migration from CJS to ESM.

eslint-cjs-to-esm

ESLint wrapper for migration from CJS to ESM.

This tool's main use-case is to migrate from CommonJS (JavaScript/TypeScript) to ES Modules (JavaScript/TypeScript).

This tool is a wrapper of ESLint, and it built-in some rules for migration. So, you can just use this tool without any configuration.

Install

Install with npm:

npm install eslint-cjs-to-esm

Usage

Command Line Arguments are the same as those of ESLint.

npx eslint-cjs-to-esm [ESLint Arguments!]

• Command Line Interface - ESLint - Pluggable JavaScript Linter

Run Lint

npx eslint-cjs-to-esm "./src/**/*.{js,ts}"

Fix Errors

npx eslint-cjs-to-esm "./src/**/*.{js,ts}" --fix

Warning You need to start with . for relative path. It is wrapper limitation.
NG: npx eslint-cjs-to-esm "src/**/*.ts"
OK: npx eslint-cjs-to-esm "./src/**/*.ts"

DEBUG:

DEBUG=eslint-cjs-to-esm npx eslint-cjs-to-esm "./src/**/*.{js,ts}"

Rules

This rule set is based on ESLint rules for migrating projects from CommonJS to ESM.

eslint-plugin-file-extension-in-import-ts

• eslint-plugin-file-extension-in-import-ts
  • [import/no-unresolved] not working for index.js · Issue #1292 · import-js/eslint-plugin-import

eslint-plugin-node

ESLint Plugin	Rule	Source	Description	Fixable
node	no-extraneous-import	🔗	disallow import declarations which import extraneous modules	-
node	no-sync	🔗	disallow synchronous methods	-
node	file-extension-in-import	🔗	enforce the style of file extensions in import declarations	Yes

eslint-plugin-import

ESLint Plugin	Rule	Source	Description	Fixable
import	extensions	🔗	Ensure consistent use of file extension within the import path.	-
import	no-unresolved	🔗	Ensure imports point to a file/module that can be resolved.	-
import	no-useless-path-segments	🔗	Prevent unnecessary path segments in import and require statements.	Yes
import	no-extraneous-dependencies	🔗	Forbid the use of extraneous packages.	-
import	no-commonjs	🔗	Report CommonJS require calls and module.exports or exports.*.	-

📝 commonjs-to-es-module-codemod helps you to migrate from require/exports(CJS) to import/export(ESM).

eslint-plugin-unicorn

ESLint Plugin	Rule	Source	Description	Fixable
unicorn	prefer-module	🔗	Prefer JavaScript modules (ESM) over CommonJS.	Yes
unicorn	prefer-node-protocol	🔗	Prefer using the node: protocol when importing Node.js builtin modules.	Yes
unicorn	prefer-top-level-await	🔗	Prefer top-level await over top-level promises and async function calls.	Suggest

• ESLint rules for migrating projects from CommonJS to ESM
• Make "import/extensions" require the .js extension in a Node.js TypeScript project - Stack Overflow

Changelog

See Releases page.

Running tests

Install devDependencies and Run npm test:

npm test

Contributing

Pull requests and stars are always welcome.

For bugs and feature requests, please create an issue.

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

Author

• azu: GitHub, Twitter

License

MIT © azu

eslint-cjs-to-esm's Issues

Not working on Windows 10

I got an error on my Windows 10 computer when I tried to run eslint.

PS C:\path\to\repository> npx eslint-cjs-to-esm "./src/**/*.{js,ts}"
C:\path\to\repository\node_modules\.bin\eslint:2
basedir=$(dirname "$(echo "$0" | sed -e 's,\\,/,g')")
          ^^^^^^^

SyntaxError: missing ) after argument list
    at internalCompileFunction (node:internal/vm:77:18)
    at wrapSafe (node:internal/modules/cjs/loader:1288:20)
    at Module._compile (node:internal/modules/cjs/loader:1340:27)
    at Module._extensions..js (node:internal/modules/cjs/loader:1435:10)
    at Module.load (node:internal/modules/cjs/loader:1207:32)
    at Module._load (node:internal/modules/cjs/loader:1023:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:135:12)
    at node:internal/main/run_main_module:28:49

Node.js v20.11.0

An error is occurring in the execution of the eslint sh file.

https://github.com/azu/eslint-cjs-to-esm/blob/main/eslint-cjs-to-esm.js#L6

I am not familiar with how eslint or npm bin works, but it seems that on Windows bat files are used instead of sh files.

Similar Issues:

• gotwarlost/istanbul#677
• jestjs/jest#4751

Specifying tsconfig in the project's .eslintrc.cjs raises parsing errors.

This library references the project's .eslintrc.cjs to run eslint.
Therefore, it may cause errors depending on the project's configuration.

Current behavior

The following command shows that this library runs eslint with reference to the project's .eslintrc.cjs.

npx eslint-cjs-to-esm --print-config  "./src/**/*.{js,ts}"

Some projects may specify tsconfig in parserOptions of .eslintrc.cjs.
https://typescript-eslint.io/linting/typed-linting/#specifying-tsconfigs

module.exports = {
    extends: [
        'eslint:recommended',
        'plugin:@typescript-eslint/recommended-type-checked',
    ],
    plugins: ['@typescript-eslint'],
    parser: '@typescript-eslint/parser',
    parserOptions: {
        project: './tsconfig.json',
    },
    root: true,
};

It causes errors.

PS C:\path\to\repository> npx eslint-cjs-to-esm "./src/index.ts"

C:\path\to\repository\src\index.ts
  0:0  error  Parsing error: Cannot read file 'c:\path\to\repository\node_modules\eslint-cjs-to-esm\tsconfig.json'

✖ 1 problem (1 error, 0 warnings)

Proposal

The project's .eslintrc.js should be ignored or command line options should be noted in README.md.

npx eslint-cjs-to-esm --no-eslintrc --no-inline-config "./src/**/*.{js,ts}" 

• --no-eslintrc: Disables use of configuration from .eslintrc.* and package.json files.
• --no-inline-config: This option prevents inline comments like /*eslint-disable*/ or /*global foo*/ from having any effect.
  • This is to avoid errors caused by comments that disable unloaded rules.

  // eslint-disable-next-line non-existing-rule

  C:\path\to\repository\index.ts
  1:1  error  Definition for rule 'non-existing-rule' was not found  non-existing-rule

Dependency Dashboard

This issue lists Renovate updates and detected dependencies. Read the Dependency Dashboard docs to learn more.

Open

These updates have all been created already. Click a checkbox below to force a retry/rebase of any.

• fix(deps): replace dependency eslint-plugin-node with eslint-plugin-n ^14.0.0
• fix(deps): update dependency @typescript-eslint/parser to v7

Detected dependencies

github-actions

.github/workflows/test.yml

• actions/checkout v4
• actions/setup-node v4

npm

package.json

• @typescript-eslint/parser ^6.21.0
• eslint-import-resolver-typescript ^3.6.1
• eslint-plugin-file-extension-in-import-ts ^2.1.0
• eslint-plugin-import ^2.29.1
• eslint-plugin-node ^11.1.0
• eslint-plugin-unicorn ^51.0.1
• execa ^8.0.1
• expected-exit-status ^3.1.0
• npm 10.5.0

---

• Check this box to trigger a request for Renovate to run again on this repository