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find-unused-exports

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A Node.js CLI and equivalent JS API to find unused ECMAScript module exports in a project.

To achieve this the whole project is analyzed at once, something ESLint can’t do as it lints files in isolation.

  • The npx find-unused-exports script is handy for finding redundant code to remove in legacy projects.
  • Use the CLI command find-unused-exports in package test scripts, so that CI can prevent the addition of redundant code.

Installation

To install with npm, run:

npm install find-unused-exports --save-dev

Then, use either the CLI command find-unused-exports or the JS API function findUnusedExports.

Ignoring unused exports

.gitignore files are used to ignore whole files or directories. This is useful for ignoring:

  • Third party modules, e.g. node_modules.
  • Compiled files, e.g. .next or dist.

Special comments can be used anywhere in a module to ignore all or specific unused exports. This is useful for ignoring intentionally unused exports intended to be imported from external code, e.g.

  • For published packages, the public exports.
  • For Next.js projects, the default exports in pages directory modules.

Examples

How to ignore all unused exports:

// ignore unused exports
export const a = true;
export default true;

How to ignore specific unused exports:

// ignore unused exports b, default
export const a = true;
export const b = true;
export default true;

Multiple comments can be used:

// ignore unused exports a
export const a = true;

// ignore unused exports b
export const b = true;

Comments are case-insensitive, except for the export names:

// iGnOrE UnUsEd eXpOrTs default

Line or block comments can be used:

/* ignore unused exports */

CLI

Command find-unused-exports

Finds unused ECMAScript module exports in a project. If some are found, it reports them to stderr and exits with a 1 error status. .gitignore files are used to ignore files.

It implements the JS API function findUnusedExports.

Arguments

Argument Default Description
--module-glob **/*.{mjs,cjs,js} JavaScript file glob pattern.
--resolve-file-extensions File extensions (without the leading ., multiple separated with , in preference order) to automatically resolve in extensionless import specifiers. Import specifier file extensions are mandatory in Node.js; if your project resolves extensionless imports at build time (e.g. Next.js, via webpack) mjs,js might be appropriate.
--resolve-index-files Should directory index files be automatically resolved in extensionless import specifiers. Node.js doesn’t do this by default; if your project resolves extensionless imports at build time (e.g. Next.js, via webpack) this argument might be appropriate. This argument only works if the argument --resolve-file-extensions is used.

Examples

Using npx in a standard Node.js project:

npx find-unused-exports

Using npx in a typical webpack project that has ESM in .js files, extensionless import specifiers, and index.js files:

npx find-unused-exports --module-glob "**/*.js" --resolve-file-extensions js --resolve-index-files

package.json scripts for a project that also uses eslint and prettier:

{
  "scripts": {
    "eslint": "eslint .",
    "prettier": "prettier -c .",
    "find-unused-exports": "find-unused-exports",
    "test": "npm run eslint && npm run prettier && npm run find-unused-exports",
    "prepublishOnly": "npm test"
  }
}

Exports

These ECMAScript modules are published to npm and exported via the package.json exports field:

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A Node.js CLI and equivalent JS API to find unused ECMAScript module exports in a project.

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