tsc-output-format

1.1.1 verified Fri May 01 auth: no javascript

tsc-output-format v1.1.1 is a TypeScript library and CLI tool that formats tsc diagnostic output into JSON, GitHub Actions annotations, grouped text, and more. Released in March 2025 with monthly updates, it supports pretty mode, watch mode, and custom formatters/parsers. Unlike other tsc output processors, it provides a pluggable architecture and first-class TypeScript types. Minimal bundle size (<5KB) and zero runtime dependencies make it suitable for CI pipelines.

Common errors

error TypeError: Cannot read properties of undefined (reading 'length') ↓

cause Passing empty or malformed input to parse().

fix

Ensure tsc output is not empty and is a string. Use parse(String(tscOutput)).

error SyntaxError: Named export 'formatGHA' not found. The requested module 'tsc-output-format' is a commonjs module... ↓

cause Importing formatGHA from the main entry (tsc-output-format) instead of subpath.

fix

import { formatGHA } from 'tsc-output-format/formatters';

Warnings

gotcha Package is ESM-only. Using require() or CommonJS will throw a runtime error. ↓

fix Use import syntax or set { "type": "module" } in package.json.

gotcha formatGHA is exported from a subpath, not the main entry. ↓

fix Import from 'tsc-output-format/formatters'.

breaking In v1.0.0, parse() did not return a 'line' property as number; it was a string. v1.1.0+ may have fixed this, but verify types. ↓

fix Upgrade to v1.1.1 or cast line to number.

Install

npm install tsc-output-format

yarn add tsc-output-format

pnpm add tsc-output-format

Imports

parse

wrong

import parse from 'tsc-output-format'

correct

import { parse } from 'tsc-output-format'

Named export, not default. ESM-only package.

format

wrong

const { format } = require('tsc-output-format')

correct

import { format } from 'tsc-output-format'

Named export. CJS is not supported; use ESM imports.

formatGHA
wrong
```
import { formatGHA } from 'tsc-output-format'
```
correct
```
import { formatGHA } from 'tsc-output-format/formatters'
```
formatGHA is exported from 'tsc-output-format/formatters' subpath, not main entry point.

Quickstart

Parses tsc diagnostic output from a TypeScript compilation and formats it as JSON.

import { parse, format } from 'tsc-output-format';
import { execSync } from 'child_process';

const tscOutput = execSync('npx tsc --noEmit 2>&1', { encoding: 'utf-8' });
const diagnostics = parse(tscOutput);
const formatted = format(diagnostics, {
  formatter: 'json', // or 'gha', 'grouped'
});
console.log(formatted);
// Output JSON array of diagnostics with file, line, column, errorCode, message.