JSPM

react-codemirror2

demo @ scniro.github.io/react-codemirror2

npm install react-codemirror2 codemirror --save

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.

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

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

props cont. (wrapped codemirror programming api)

• cursor - setCursor

  will programmatically set cursor to the position specified

<CodeMirror
  [...]
  cursor={{
    line: 5,
    ch: 10
  }}
  onCursor={(editor, data) => {}}
/>

• scroll - scrollTo

  will programmatically scroll to the specified coordinate

<CodeMirror
  [...]
  scroll={{
    x: 50,
    y: 50
  }}
  onScroll={(editor, data) => {}}
/>

• selection={array<{anchor, head}>} - setSelections

  will programmatically select the ranges specified

<CodeMirror
  [...]
  selection={[{
    anchor: {ch: 8, line: 5},
    head: {ch: 37, line: 5}
  }]}
  onSelection={(editor, data) => {}}
/>

events

events cont. wrapped codemirror events

• onBlur(editor, event) - blur
• onCursor(editor, data)- cursorActivity
• onCursorActivity(editor) - cursorActivity
• onDragEnter(editor, event) - dragenter
• onDragOver(editor, event) - dragover
• onDrop(editor, event) - drop
• onFocus(editor, event) - focus
• onGutterClick(editor, lineNumber, gutter, event) - gutterClick
• onKeyDown(editor, event) - keydown
• onKeyPress(editor, event) - keypress
• onKeyUp(editor, event) - keyup
• onScroll(editor, data) - scroll
• onSelection(editor, data) - beforeSelectionChange
• onUpdate(editor, event) - update
• onViewportChange(editor, from, to) - viewportChange

misc. notes

• server rendering

react-codemirror2 will prevent rendering in absence of navigator that is typical of a server environment. In case of any issue, you can force the component to not render via a PREVENT_CODEMIRROR_RENDER global variable that this wrapper respond to.

• getting the instance

getting the instance of the underlying editor can be done via the event callbacks where editor is returned. There is no static method to get it on demand, e.g. CodeMirror.getInstance(). The recommended approach can be observed as follows...

constructor() {
  this.instance = null;
}

render() {
  <CodeMirror editorDidMount={editor => { this.instance = editor }}/>
}

MIT © 2018 scniro