eslint-formatter-mo

2.4.1 verified Sat Apr 25 auth: no javascript

Good-lookin' ESLint formatter for delightful readability. Current stable version is 2.4.1, released November 2025, with regular updates. Key differentiators: colorful output with code highlighting via Shiki, support for 50+ VS Code themes, JSON/Markdown/CSS highlighting, and auto-fixable markers. ESM-only since v2 (breaking change). Active maintenance with frequent bug fixes.

Common errors

error Cannot find module 'eslint-formatter-mo' ↓

cause Package not installed or not in node_modules.

fix

Run npm install eslint-formatter-mo --save-dev.

error require() of ES Module eslint-formatter-mo from CommonJS not supported. ↓

cause Using CommonJS require() with ESM-only v2+.

fix

Use import syntax or downgrade to v1.x (not recommended).

error Error: Cannot access 'ruleId' before initialization ↓

cause Bug in v2.4.0 fixed in v2.4.1.

fix

Upgrade to v2.4.1 or later.

Warnings

breaking v2.0.0 moved to ESM only. CommonJS require() will throw an error. ↓

fix Use import syntax or upgrade to Node 18+ with "type": "module" in package.json.

deprecated v1.x is no longer maintained. Users should upgrade to v2.x. ↓

fix Upgrade to v2.4.1 and migrate to ESM.

gotcha The formatter uses Shiki for syntax highlighting, which requires network access for theme loading on first use. ↓

fix Ensure network access or pre-cache themes. The package will work without highlighting if offline.

gotcha Environment variable MO_THEME must be set before running ESLint, not during. ↓

fix Set MO_THEME in your shell or .env file before calling eslint.

gotcha Output is designed for terminals; may not render correctly in CI logs or non-TTY environments. ↓

fix Use --no-color or pipe output to a file for non-TTY environments.

Install

npm install eslint-formatter-mo

yarn add eslint-formatter-mo

pnpm add eslint-formatter-mo

Imports

default

wrong

const eslintFormatterMo = require('eslint-formatter-mo')

correct

import eslintFormatterMo from 'eslint-formatter-mo'

ESM-only since v2; CommonJS require will fail.

default (as formatter function)

wrong

const mo = require('eslint-formatter-mo');

correct

import mo from 'eslint-formatter-mo'; eslint.lintFiles(patterns).then(results => console.log(mo(results)))

The default export is a function that takes ESLint results and returns a formatted string.

TypeScript type (if provided)
```
import type { ESLintFormatter } from 'eslint-formatter-mo'
```
Types may be bundled; check package for type definitions.

Quickstart

Shows installation as dev dependency, CLI usage with `-f mo`, programmatic use with import, and custom theme via environment variable.

// Install: npm i eslint-formatter-mo -D
// Use as ESLint formatter via CLI:
// eslint src/ -f mo
// Or programmatically:
import mo from 'eslint-formatter-mo';
import { ESLint } from 'eslint';

const eslint = new ESLint();
const results = await eslint.lintFiles(['src/']);
const formatted = mo(results);
console.log(formatted);

// Custom theme via env var:
// MO_THEME=dracula eslint src/ -f mo