publint

0.3.18 verified Fri May 01 auth: no javascript

publint is a tool for linting npm packaging errors to ensure compatibility across environments. The current stable version is 0.3.18, with frequent patch releases addressing edge cases in export mapping, file existence checks, and CJS/ESM interop warnings. It differentiates from tsc or api-extractor by focusing specifically on package.json validation, including exports, imports, main, types fields, and CommonJS default export issues. It provides a CLI, API, and online playground, and supports Node >=18.

Common errors

error SyntaxError: Unexpected token '?' ↓

cause Using Node <18 which lacks support for ?? operator in publint code

fix

Upgrade Node to 18 or later.

error ERR_MODULE_NOT_FOUND: Cannot find module 'publint' ↓

cause Using CommonJS require() with ESM-only package

fix

Add "type": "module" in package.json and use import statements.

error Error: Cannot find module 'publint/utils' ↓

cause Incorrect import path; utility exports are under 'publint/utils' subpath

fix

Import from 'publint/utils' instead of 'publint'.

Warnings

breaking Requires Node >=18; older versions will fail ↓

fix Upgrade Node to >=18.

breaking ESM-only since v0.3.0; CommonJS require will not work ↓

fix Use import statements instead of require().

deprecated Some rules may change severity in future; check docs ↓

fix Stay updated via changelog.

Install

npm install publint

yarn add publint

pnpm add publint

Imports

publint

wrong

import publint from 'publint'

correct

import { publint } from 'publint'

publint is a named export, not default.

check

wrong

const check = require('publint').check

correct

import { check } from 'publint'

ESM-only since v0.3.0; CommonJS require may fail.

getPkgPathValue

wrong

import { getPkgPathValue } from 'publint'

correct

import { getPkgPathValue } from 'publint/utils'

Utility functions are in 'publint/utils' subpath.

Quickstart

Demonstrates using the publint API to lint a package.json and print formatted messages.

import { check, formatMessage } from 'publint';
import { readFile } from 'node:fs/promises';

const pkgJson = JSON.parse(await readFile('./package.json', 'utf-8'));
const results = await check({ pkg: pkgJson, rootDir: '.' });
for (const msg of results.messages) {
  console.log(formatMessage(msg));
}