Registry / testing / eslint-flat-config-utils

eslint-flat-config-utils

library3.1.0jsnpmunverified

Utils for managing and manipulating ESLint flat config arrays. Current stable version is 3.1.0, released actively by antfu. Provides helpers like concat (flatten and merge configs/promises), composer (chainable API for appending, prepending, inserting, renaming plugins, overriding rules, removing rules, and disabling rule fixes), and resolveExtends for extending configs. Differentiators: chainable composer extends Promise for direct use in eslint.config.mjs; renamePlugins, removeRules, disableRulesFix are unique helpers not found in standard ESLint utilities. ESM-only since v2.0.0, TypeScript-ready with shipped types, and supports @eslint/config-helpers for extends resolution since v3.0.0.

testing

npm install eslint-flat-config-utils

github ↗package ↗

INSTALL

IMPORT

SIG · ESLINT-FLAT-CONFIG

eslint-flat-config-utils

testingjavascriptv3.1.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

concat

✓ import { concat } from 'eslint-flat-config-utils'

✗ const { concat } = require('eslint-flat-config-utils')

ESM-only since v2.0.0; require() will fail.

composer

✓ import { composer } from 'eslint-flat-config-utils'

✗ import composer from 'eslint-flat-config-utils'

Default import is not available; composer is a named export.

ConfigNames

✓ import { ConfigNames } from 'eslint-flat-config-utils'

✗ import { ConfigName } from 'eslint-flat-config-utils'

Type export for config names used in composer.override, etc. Plurals only.

resolveExtends

✓ import { resolveExtends } from 'eslint-flat-config-utils'

Introduced in v3.0.0 to handle extends resolution via @eslint/config-helpers.

Chain composer to merge, rename and remove rules in ESLint flat config.

import { composer } from 'eslint-flat-config-utils' const config = await composer( { name: 'base', plugins: { 'my-plugin': { rules: { 'my-rule': 'error' } } }, rules: { 'my-plugin/my-rule': 'error' } }, { name: 'typescript', files: ['*.ts'], rules: { 'no-console': 'warn' } } ) .override('typescript', { rules: { 'no-console': 'off' } }) .renamePlugins({ 'my-plugin': 'renamed' }) .removeRules('no-console') export default config

Debug

Known issues

breakingv2.0.0 dropped CommonJS support; now ESM-only.

fix

Convert require() to import statements and ensure package.json has 'type': 'module'.

affects: >=2.0.0

deprecatedv2.x resolveExtends behavior changed in v3.0.0 to require @eslint/config-helpers.

fix

Update code to use new resolveExtends signature or update imports if previously using older version.

affects: >=3.0.0

gotchacomposer.renamePlugins only applies to plugins and rules present in the config array; does not mutate original objects.

fix

Always await/reassign the composer result to get the renamed config.

affects: >=1.0.0

gotchadisableRulesFix hijacks plugin's meta.fixable property; may not work with all plugins (e.g., those that cache fixable status).

fix

Test with targeted plugins; consider alternative like overriding rule options with meta.fixable: null if supported.

affects: >=1.1.0

breakingv3.0.0 changed config resolution for extends; previous behavior (string extends) now handled by @eslint/config-helpers.

fix

Ensure @eslint/config-helpers is installed if using extends in config files.

affects: >=3.0.0

Errors

Common errors & fixes

Error [ERR_REQUIRE_ESM]: require() of ES Module /path/to/node_modules/eslint-flat-config-utils/index.mjs not supported.

Package is ESM-only since v2.0.0; require() fails in CommonJS context.

fix

Use dynamic import() or switch to ESM: add 'type': 'module' to package.json and replace require() with import.

TypeError: composer(...).append is not a function

composer call not awaited or not properly chained after async operations.

fix

Ensure the composer chain is properly written: await composer(...).append(...); or use the fluent API synchronously.

Cannot find module 'eslint-flat-config-utils' or its corresponding type declarations.

Missing installation or TypeScript cannot resolve the package types.

fix

Install the package: npm install eslint-flat-config-utils. For TypeScript, ensure tsconfig.json includes 'moduleResolution': 'node' or 'bundler'.

TypeError: Cannot destructure property 'concat' of '...' as it is undefined.

Attempted to require() named export in CJS after v2.0.0, but package no longer exports CJS.

fix

Use import { concat } from 'eslint-flat-config-utils' or call dynamic import().

Upgrade

Version history

3.1.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/antfu/eslint-flat-config-utils ↗

packagehttps://www.npmjs.com/package/eslint-flat-config-utils ↗