react-codemirror2

react-codemirror2 ships with the notion of an uncontrolled and controlled component. UnControlled consists of a simple wrapper largely powered by the inner workings of codemirror itself, while Controlled will demand state management from the user, preventing codemirror changes unless properly handled via value. The latter will offer more control and likely be more appropriate with redux heavy apps.

npm install react-codemirror2 codemirror --save
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uncontrolled usage

import {UnControlled as CodeMirror} from 'react-codemirror2'

<CodeMirror
  value='<h1>I ♥ react-codemirror2</h1>'
  options={{
    mode: 'xml',
    theme: 'material',
    lineNumbers: true
  }}
  onChange={(editor, data, value) => {
  }}
/>

controlled usage

import {Controlled as CodeMirror} from 'react-codemirror2'

<CodeMirror
  value={this.state.value}
  options={options}
  onBeforeChange={(editor, data, value) => {
    this.setState({value});
  }}
  onChange={(editor, data, value) => {
  }}
/>

requiring codemirror resources

codemirror comes as a peer dependency, meaning you'll need to require it in your project in addition to react-codemirror2. This prevents any versioning conflicts that would arise if codemirror came as a dependency through this wrapper. It's been observed that version mismatches can cause difficult to trace issues such as sytax highlighting disappearing without any explicit errors/warnings

  • additional

Since codemirror ships mostly unconfigured, the user is left with the responsibility for requiring any additional resources should they be necessary. This is often the case when specifying certain language modes and themes. How to import/require these assets will vary according to the specifics of your development environment. Below is a sample to include the assets necessary to specify a mode of xml (HTML) and a material theme.

note that the base codemirror.css file is required in all use cases

@import 'codemirror/lib/codemirror.css';
@import 'codemirror/theme/material.css';

import CodeMirror from 'react-codemirror2';
require('codemirror/mode/xml/xml');
require('codemirror/mode/javascript/javascript');

props

prop type default components description
autoCursor boolean true Controlled UnControlled should component cursor position correct when value changed
autoScroll boolean true Controlled UnControlled should component scroll cursor position into view when value changed
className string Controlled UnControlled pass through class class="react-codemirror2 className"
defineMode object Controlled UnControlled pass a custom mode via {name: 'custom', fn: myModeFn}
detach boolean UnControlled should component ignore new props
options object Controlled UnControlled codemirror configuration
value string *Controlled UnControlled * component value must be managed for controlled components

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