twoslash-eslint

0.3.8 verified Sat Apr 25 auth: no javascript

ESLint-backed twoslash runner for annotating code examples with ESLint errors and warnings. Current stable version is 0.3.8, released on a monthly cadence. Key differentiators: integrates ESLint diagnostic results directly into twoslash code blocks, supports TypeScript v6 since v0.3.7, and is part of the twoslash monorepo. Experimental — breaking changes may not follow semver. Ships TypeScript types.

Common errors

error ERR_REQUIRE_ESM: require() of ES Module not supported ↓

cause Using CommonJS require() to import an ESM-only package.

fix

Use dynamic import: const m = await import('twoslash-eslint') or set your project to type: module.

error Cannot find module 'twoslash-eslint' ↓

cause Package not installed or missing from package.json dependencies.

fix

Run npm install twoslash-eslint (peer dep eslint must also be installed).

Warnings

breaking Since v0.3.0, TypeScript ^5.5.0 is explicitly required. Older TypeScript versions are unsupported. ↓

fix Upgrade TypeScript to >=5.5.0 or stay on v0.2.x if you need older TS support.

gotcha The package is experimental and breaking changes may not follow semver. ↓

fix Pin to a specific version and test upgrades carefully.

deprecated The `writeGlobalTypes` option was removed in v0.3.5 for Vue integration. ↓

fix Remove `writeGlobalTypes` from configuration. Use other Vue type handling mechanisms if needed.

Install

npm install twoslash-eslint

yarn add twoslash-eslint

pnpm add twoslash-eslint

Imports

createTwoslashESLint

wrong

const createTwoslashESLint = require('twoslash-eslint')

correct

import { createTwoslashESLint } from 'twoslash-eslint'

ESM-only package; CommonJS require() will fail. Use dynamic import or ESM context.

default
```
import twoslashESLint from 'twoslash-eslint'
```
Default export is an alias for createTwoslashESLint. Available since v0.2.0.
TypeScriptESLintRunner
wrong
```
import { TypeScriptESLintRunner } from 'twoslash'
```
correct
```
import { TypeScriptESLintRunner } from 'twoslash-eslint'
```
TypeScriptESLintRunner is a custom runner class exported from twoslash-eslint, not from core twoslash.

Quickstart

Creates an ESLint-backed twoslash runner and applies it to a code example with a custom ESLint rule.

import { createTwoslashESLint } from 'twoslash-eslint'
import { createTwoslash } from 'twoslash'

const twoslashESLint = createTwoslashESLint({
  eslint: {
    // ESLint options
    overrideConfig: {
      rules: { 'no-unused-vars': 'warn' }
    }
  }
})

const result = createTwoslash({
  code: 'let x = 1',
  defaultCompilerOptions: { strict: true },
  customRunners: [twoslashESLint]
})