base-lint

library1.2.1jsnpmunverified

base-lint scans repositories for usage of modern Web Platform features and evaluates them against the Baseline dataset to ensure new features ship with fallbacks. Version 1.2.1 is current, with active maintenance and a GitHub Action for CI integration. Key differentiators include diff-mode analysis (default), Markdown and JSON reports, threshold-based enforcement (base-lint enforce), GitHub Checks annotation (base-lint annotate), and PR comment creation (base-lint comment). It relies on @typescript-eslint/typescript-estree for parsing TypeScript/JavaScript, requiring Node.js 18.17+ or 20.x LTS. Alternatives like Lighthouse or caniuse require external dataset integration, whereas base-lint provides an out-of-the-box CLI with built-in Baseline compliance tooling.

testing devops

npm install base-lint

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · BASE-LINT

base-lint

testingjavascriptv1.2.1

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

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

default

✓ import baseLint from 'base-lint'

✗ const baseLint = require('base-lint')

The package is ESM-only since v1.2.0; CommonJS require() will fail.

scan

✓ import { scan } from 'base-lint'

✗ const { scan } = require('base-lint')

Named export available for programmatic use; ESM import must use named syntax.

enforce

✓ import { enforce } from 'base-lint'

✗ import enforce from 'base-lint/enforce'

enforce is a top-level named export, not a submodule.

Demonstrates programmatic usage of init, scan, enforce, and clean functions with ESM imports.

// Initialize a new base-lint configuration and run a diff scan import { scan, init, clean } from 'base-lint'; import { writeFileSync, mkdirSync, existsSync } from 'fs'; import { resolve } from 'path'; async function main() { // Step 1: Initialize config (scaffold .base-lintrc.json, .base-lintignore) await init({ cwd: process.cwd() }); // Step 2: Scan the current diff (default mode) and get report const result = await scan({ cwd: process.cwd(), mode: 'diff', // or 'repo' for full scan outputDir: '.base-lint-report', }); console.log('Report generated at:', result.outputPath); // Step 3: Enforce thresholds (e.g., max violations: 0) const enforceResult = await enforce({ reportPath: resolve('.base-lint-report/report.json'), thresholds: { errors: 0, warnings: 5 }, }); if (!enforceResult.passed) { console.error('Enforcement failed:', enforceResult.violations); process.exit(1); } // Step 4: Clean up report artifacts (optional) await clean({ outputDir: '.base-lint-report' }); } main().catch(console.error);

base-lint --version

Debug

Known issues

breakingESM-only since v1.2.0: package no longer supports CommonJS require().

fix

Use import instead of require; for CommonJS projects, upgrade to Node.js 20+ and use dynamic import or await import().

affects: >=1.2.0

deprecatedbase-lint init --action flag is deprecated; use --github-action instead.

fix

Replace '--action' with '--github-action' when scaffolding GitHub Action workflow.

affects: >=1.1.0

gotchaDiff mode (default) only scans staged changes; uncommitted files are ignored unless --mode=repo is passed.

fix

Ensure all changes are staged (git add) before running base-lint scan, or use --mode=repo for full codebase scan.

affects: *

breakinRemoved caching in v1.1.1 due to bundle size bloat; cache support no longer available.

fix

Remove any cache configuration from .base-lintrc.json; manual caching via CI artifacts is still possible.

affects: >=1.1.1

gotchaTypeScript parsing errors may occur with TS versions not supported by @typescript-eslint/typescript-estree.

fix

Check @typescript-eslint/typescript-estree peer dependency version and keep TypeScript within supported range (≤5.4.x).

affects: *

Errors

Common errors & fixes

Error [ERR_REQUIRE_ESM]: require() of ES Module /path/to/node_modules/base-lint/dist/index.js from /path/to/project/index.js not supported.

Using CommonJS require() on an ESM-only package (v1.2.0+).

fix

Switch to ESM (type: module in package.json) and use import statements, or use dynamic import: const baseLint = await import('base-lint');

Error: Command 'scan' failed with exit code 1: No staged changes found. Use --mode=repo to scan the entire repository.

Running diff mode without any staged files in git.

fix

Stage changes with git add before running scan, or pass --mode=repo for full scan.

TypeScript Error: Cannot find module 'base-lint' or its corresponding type declarations.

Typings not installed; base-lint requires @types/base-lint for TypeScript.

fix

Run npm install --save-dev @types/base-lint (note: typings may be bundled in future versions).

Upgrade

Version history

1.2.1latest on npm

Audit

Dependencies

@typescript-eslint/typescript-estreeoptionalParses TypeScript and JavaScript source files to detect feature usage.

@typescript-eslint/parseroptionalAlternative parser for ESLint integration (not directly required by CLI but commonly used).

Agent activity

20 hits · last 30 days

node

Amazon

OpenAI (training)

Resources

githubhttps://github.com/ej-sanmartin/base-lint ↗

packagehttps://www.npmjs.com/package/base-lint ↗

homepagehttps://base-lint.dev ↗