npm-check-updates 21.0.0

[21.0.0] - 2026-04-14

This is a major breaking change with significant architectural updates.

Pure ESM: Converted to pure ESM with dual-build support (ESM/CJS) via Vite 8.
Import Syntax: Programmatic usage now requires named imports or namespace imports.
- Old: import ncu from 'npm-check-updates'
- New: import * as ncu from 'npm-check-updates' or import { run } from 'npm-check-updates'
Node.js Requirements: Now requires ^20.19.0 || ^22.12.0 || >=24.0.0. This is required for native require(esm) support and the Rolldown engine.
npm Requirements: Minimum version increased to >=10.0.0.

Files named .ncurc.js that use module.exports will now fail in projects that are not "type": "module".
Fix: Rename these files to .ncurc.cjs or convert them to use export default.

Vite 8 Upgrade: Migrated to Vite 8 with the new Rust-based Rolldown bundler (10-30x faster builds).
TypeScript 6.0: Adopted latest type-system features and performance improvements.
Strip ANSI: Replaced strip-ansi with Node.js built-in util.stripVTControlCharacters.
Test Runner: Replaced vite-node with tsx for TypeScript support in ESM context.

If you are upgrading to v21 from earlier versions:

Ensure you meet the new Node.js requirement: ^20.19.0 || ^22.12.0 || >=24.0.0.
Update npm to at least 10.0.0.

If you have a .ncurc.js file:

Option B: Convert it to ESM:

import { defineConfig } from 'npm-check-updates'

export default defineConfig({
  upgrade: true,
  filter: name => name.startsWith('@myorg/'),
})

If you import npm-check-updates in your scripts:

ESM: Change import ncu from ... to import * as ncu from 'npm-check-updates'.
CommonJS: Ensure you are destructuring the named exports or using the full object:

const ncu = require('npm-check-updates')
// Use ncu.run(...)

Tests now use tsx for module loading. When running tests manually:

mocha --node-option import=tsx 'test/**/*.test.ts'

Or use the npm script:

npm test