eslint-import-resolver-lerna

2.0.0 verified Sat Apr 25 auth: no javascript

Resolver for eslint-plugin-import that enables module resolution in Lerna-based monorepos. Version 2.0.0 (latest, Nov 2020) is a rewrite to TypeScript with breaking changes from 1.x. It maps packages defined in Lerna's packages directories so that eslint-plugin-import can resolve cross-package imports, particularly needed when using compilation pipelines (Babel, TypeScript) that output to a different directory. Unlike the built-in Node resolver, this supports non-standard packages directories and helps avoid "Unable to resolve path to module" errors in monorepos.

Common errors

error Unable to resolve path to module './packages/foo'. ↓

cause eslint-plugin-import cannot find the internal package without the resolver.

fix

Add the lerna resolver configuration in .eslintrc as shown in quickstart.

error Error: Cannot find module 'eslint-import-resolver-lerna' ↓

cause Missing or misconfigured peer dependency eslint-plugin-import.

fix

Install eslint-plugin-import as a dev dependency: npm i -D eslint-plugin-import

error TypeError: resolver.create is not a function ↓

cause Using require() for v2 which is ESM-only.

fix

Change to import syntax in an ESM context or downgrade to v1.

error The "packages" option must be a string or array of strings. ↓

cause Invalid type passed to packages option.

fix

Ensure packages is a string path or array of absolute paths.

Warnings

breaking Version 2.0.0 drops CommonJS support; package is now ESM-only. ↓

fix Use import syntax; if you need CJS, stay on 1.x or use dynamic import.

breaking The default export changed from a function to an object in v2.0.0. ↓

fix Use named exports: import { resolve, resolveSync } from the package.

deprecated The 'packages' option no longer accepts relative paths in some ESLint contexts. ↓

fix Always use absolute paths, e.g., path.resolve(__dirname, 'packages').

gotcha The resolver expects package.json files in the packages subdirectories; missing ones cause silent failures. ↓

fix Ensure every package subdirectory has a package.json with a valid 'name' field.

gotcha The resolver does not automatically detect Lerna's lerna.json; 'packages' option is mandatory. ↓

fix Always specify the 'packages' setting pointing to the packages directory.

Install

npm install eslint-import-resolver-lerna

yarn add eslint-import-resolver-lerna

pnpm add eslint-import-resolver-lerna

Imports

default

wrong

const resolver = require('eslint-import-resolver-lerna')

correct

import resolver from 'eslint-import-resolver-lerna'

ESM-only since v2; CJS require will not work with default export.

resolveSync

wrong

import { resolve } from 'eslint-import-resolver-lerna'

correct

import { resolveSync } from 'eslint-import-resolver-lerna'

resolveSync is the named export for synchronous resolution; resolve does not exist.

resolve

wrong

import { resolve as syncResolve } from 'eslint-import-resolver-lerna'

correct

import { resolve } from 'eslint-import-resolver-lerna'

resolve is a named export returning a promise (async). Not to be confused with resolveSync.

Quickstart

Configure eslint-plugin-import to use lerna resolver for packages directory.

// .eslintrc.js
module.exports = {
  settings: {
    'import/resolver': {
      'eslint-import-resolver-lerna': {
        packages: __dirname + '/packages'
      }
    }
  }
};