CodeMirror Formatting Addon

1.0.0 verified Sat Apr 25 auth: no javascript

A standalone, modular packaging of the original CodeMirror formatting addon (v1.0.0), designed to simplify inclusion in module-based projects. Originally extracted from the official CodeMirror v2 demo page, this package provides basic code formatting capabilities (auto-indent and comment toggling) for CodeMirror editors. The release cadence is low; the package has been stable since 2016. Unlike the built-in formatting in CodeMirror v5+, this addon is compatible with older CodeMirror versions (2.x) and does not require a full migration. It ships as a single JavaScript file and is intended for use with browser module loaders or bundlers.

Common errors

error Error: Cannot find module 'codemirror-formatting' ↓

cause Package not installed or not resolved by bundler.

fix

Run npm install codemirror-formatting or add it to package.json.

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

cause CodeMirror is not loaded before the formatting addon is imported.

fix

Ensure CodeMirror is imported and available globally (e.g., import 'codemirror' before 'codemirror-formatting').

error 'indentMore' is not a known command ↓

cause The formatting addon has not been applied properly, or using CodeMirror v5+ which has its own commands.

fix

Verify that the addon is imported and that you are using a compatible CodeMirror version (2.x–4.x).

Warnings

breaking This addon only works with CodeMirror versions 2.x~4.x. It does not support CodeMirror v5+ (which has built-in formatting). ↓

fix Upgrade to CodeMirror v5+ and use its built-in formatting commands (e.g., indentMore, indentLess).

gotcha The addon modifies CodeMirror.commands globally. If using multiple editor instances, all will be affected. ↓

fix Ensure this import is only done once in your application.

deprecated This package has not been updated since 2016 and may have compatibility issues with modern bundlers. ↓

fix Consider using the official CodeMirror formatting addon from @codemirror/format or codemirror/addon/comment/comment.js.

gotcha The 'autoIndent' command may not work as expected if the CodeMirror mode does not support indentation. ↓

fix Test with your specific mode or use a mode that defines indentUnit.

Install

npm install codemirror-formatting

yarn add codemirror-formatting

pnpm add codemirror-formatting

Imports

default (formatting module)
wrong
```
import formatting from 'codemirror-formatting'
```
correct
```
import 'codemirror-formatting'
```
The module has no default export; it patches the global CodeMirror object.

CodeMirrorCommands (if using named import)

wrong

import { indentMore } from 'codemirror-formatting'

correct

import 'codemirror-formatting'; // then use CodeMirror.commands.indentMore, etc.

Commands are added to CodeMirror.commands; no named exports are available.

CommonJS require
```
require('codemirror-formatting')
```
Works with Node.js/bundlers. The module side-effects CodeMirror global.
TypeScript types
wrong
```
import type {} from 'codemirror-formatting'
```
correct
```
/// <reference types="codemirror-formatting" />
```
Type definitions are not bundled; use a .d.ts file or add triple-slash reference.

Quickstart

Shows how to import the formatting addon and use its commands (indentMore, indentLess, autoIndent, toggleComment) on a CodeMirror editor.

// Ensure CodeMirror is loaded first. Then import the formatting addon.
// It automatically extends CodeMirror.commands.
import CodeMirror from 'codemirror';
import 'codemirror/lib/codemirror.css';
import 'codemirror/mode/javascript/javascript';
import 'codemirror-formatting';

const editor = CodeMirror(document.getElementById('editor'), {
  mode: 'javascript',
  lineNumbers: true
});

// Use the formatting commands:
editor.execCommand('indentMore');     // Indent selection
editor.execCommand('indentLess');     // Unindent selection
editor.execCommand('autoIndent');     // Auto-indent selection or line
editor.execCommand('toggleComment');  // Toggle line comment