@uiw/react-codemirror

What is @uiw/react-codemirror?

@uiw/react-codemirror is a React component for CodeMirror, a versatile text editor implemented in JavaScript for the browser. It provides a flexible and customizable code editor with support for various programming languages, themes, and extensions.

What are @uiw/react-codemirror's main functionalities?

Basic Usage

This code demonstrates the basic usage of @uiw/react-codemirror. It imports the necessary modules and sets up a simple CodeMirror editor with JavaScript syntax highlighting.

import React from 'react';
import CodeMirror from '@uiw/react-codemirror';
import { javascript } from '@codemirror/lang-javascript';

const App = () => {
  return (
    <CodeMirror
      value="console.log('Hello, world!');"
      height="200px"
      extensions={[javascript()]}
    />
  );
};

export default App;

Theming

This example shows how to apply a theme to the CodeMirror editor. The 'oneDark' theme is imported and added to the extensions array.

import React from 'react';
import CodeMirror from '@uiw/react-codemirror';
import { javascript } from '@codemirror/lang-javascript';
import { oneDark } from '@codemirror/theme-one-dark';

const App = () => {
  return (
    <CodeMirror
      value="console.log('Hello, world!');"
      height="200px"
      extensions={[javascript(), oneDark]}
    />
  );
};

export default App;

Handling Events

This code demonstrates how to handle change events in the CodeMirror editor. The 'handleChange' function logs the new value to the console whenever the content changes.

import React from 'react';
import CodeMirror from '@uiw/react-codemirror';
import { javascript } from '@codemirror/lang-javascript';

const App = () => {
  const handleChange = (value, viewUpdate) => {
    console.log('Value changed:', value);
  };

  return (
    <CodeMirror
      value="console.log('Hello, world!');"
      height="200px"
      extensions={[javascript()]}
      onChange={handleChange}
    />
  );
};

export default App;

Other packages similar to @uiw/react-codemirror

react-codemirror2

react-codemirror2 is another React wrapper for CodeMirror. It provides similar functionality to @uiw/react-codemirror but with a different API. It supports various CodeMirror features and is widely used in the React community.

react-ace

react-ace is a React component for the Ace editor. While it serves a similar purpose to @uiw/react-codemirror, it uses the Ace editor instead of CodeMirror. It offers a wide range of features and is known for its performance and flexibility.

react-monaco-editor

react-monaco-editor is a React component for the Monaco editor, which powers Visual Studio Code. It provides a highly customizable and feature-rich code editor experience, making it a strong alternative to @uiw/react-codemirror for more advanced use cases.

README

react-codemirror

CodeMirror component for React. Demo Preview: @uiwjs.github.io/react-codemirror

Features:

🚀 Quickly and easily configure the API.
🌱 Versions after @uiw/react-codemirror@v4 use codemirror 6. #88.
⚛️ Support the features of React Hook(requires React 16.8+).
📚 Use Typescript to write, better code hints.
🌐 The bundled version supports use directly in the browser #267.
🌎 There are better sample previews.
🎨 Support theme customization, provide theme editor.

Install

Not dependent on uiw.

npm install @uiw/react-codemirror --save

All Packages

Name	NPM Version	Website
@uiw/react-codemirror		#preview
react-codemirror-merge		#preview
@uiw/codemirror-extensions-basic-setup		#preview
@uiw/codemirror-extensions-color		#preview
@uiw/codemirror-extensions-classname		#preview
@uiw/codemirror-extensions-events		#preview
@uiw/codemirror-extensions-hyper-link		#preview
@uiw/codemirror-extensions-langs		#preview
@uiw/codemirror-extensions-line-numbers-relative		#preview
@uiw/codemirror-extensions-mentions		#preview
@uiw/codemirror-extensions-zebra-stripes		#preview
@uiw/codemirror-themes		#preview

Name	NPM Version	Website
@uiw/codemirror-themes-all		#preview
@uiw/codemirror-theme-abcdef		#preview
@uiw/codemirror-theme-androidstudio		#preview
@uiw/codemirror-theme-atomone		#preview
@uiw/codemirror-theme-aura		#preview
@uiw/codemirror-theme-bbedit		#preview
@uiw/codemirror-theme-bespin		#preview
@uiw/codemirror-theme-duotone		#preview
@uiw/codemirror-theme-dracula		#preview
@uiw/codemirror-theme-darcula		#preview
@uiw/codemirror-theme-eclipse		#preview
@uiw/codemirror-theme-github		#preview
@uiw/codemirror-theme-gruvbox-dark		#preview
@uiw/codemirror-theme-material		#preview
@uiw/codemirror-theme-noctis-lilac		#preview
@uiw/codemirror-theme-nord		#preview
@uiw/codemirror-theme-okaidia		#preview
@uiw/codemirror-theme-solarized		#preview
@uiw/codemirror-theme-sublime		#preview
@uiw/codemirror-theme-tokyo-night		#preview
@uiw/codemirror-theme-tokyo-night-storm		#preview
@uiw/codemirror-theme-tokyo-night-day		#preview
@uiw/codemirror-theme-vscode		#preview
@uiw/codemirror-theme-xcode		#preview

Usage

import React from 'react';
import CodeMirror from '@uiw/react-codemirror';
import { javascript } from '@codemirror/lang-javascript';

function App() {
  const onChange = React.useCallback((value, viewUpdate) => {
    console.log('value:', value);
  }, []);
  return (
    <CodeMirror
      value="console.log('hello world!');"
      height="200px"
      extensions={[javascript({ jsx: true })]}
      onChange={onChange}
    />
  );
}
export default App;

Support Language

import CodeMirror from '@uiw/react-codemirror';
import { StreamLanguage } from '@codemirror/language';
import { go } from '@codemirror/legacy-modes/mode/go';

const goLang = `package main
import "fmt"

func main() {
  fmt.Println("Hello, 世界")
}`;

export default function App() {
  return <CodeMirror value={goLang} height="200px" extensions={[StreamLanguage.define(go)]} />;
}

• @codemirror/legacy-modes/mode/cpp => @codemirror/lang-cpp
• @codemirror/legacy-modes/mode/html => @codemirror/lang-html
• @codemirror/legacy-modes/mode/java => @codemirror/lang-java
• @codemirror/legacy-modes/mode/javascript => @codemirror/lang-javascript
• @codemirror/legacy-modes/mode/json => @codemirror/lang-json
• @codemirror/legacy-modes/mode/lezer => @codemirror/lang-lezer
• @codemirror/legacy-modes/mode/markdown => @codemirror/lang-markdown
• @codemirror/legacy-modes/mode/php => @codemirror/lang-php
• @codemirror/legacy-modes/mode/python => @codemirror/lang-python
• @codemirror/legacy-modes/mode/rust => @codemirror/lang-rust
• @codemirror/legacy-modes/mode/sql => @codemirror/lang-sql
• @codemirror/legacy-modes/mode/xml => @codemirror/lang-xml
• @codemirror/legacy-modes/mode/css => @codemirror/lang-less
• @codemirror/legacy-modes/mode/sass => @codemirror/lang-sass
• @codemirror/legacy-modes/mode/clojure => @nextjournal/lang-clojure
• @codemirror/legacy-modes/mode/clike => @replit/codemirror-lang-csharp

Markdown Example

Markdown language code is automatically highlighted.

import CodeMirror from '@uiw/react-codemirror';
import { markdown, markdownLanguage } from '@codemirror/lang-markdown';
import { languages } from '@codemirror/language-data';

const code = `## Title

\`\`\`jsx
function Demo() {
  return <div>demo</div>
}
\`\`\`

\`\`\`bash
# Not dependent on uiw.
npm install @codemirror/lang-markdown --save
npm install @codemirror/language-data --save
\`\`\`

[weisit ulr](https://uiwjs.github.io/react-codemirror/)

\`\`\`go
package main
import "fmt"
func main() {
  fmt.Println("Hello, 世界")
}
\`\`\`
`;

export default function App() {
  return <CodeMirror value={code} extensions={[markdown({ base: markdownLanguage, codeLanguages: languages })]} />;
}

Codemirror Merge

import CodeMirrorMerge from 'react-codemirror-merge';
import { EditorView } from 'codemirror';
import { EditorState } from '@codemirror/state';

const Original = CodeMirrorMerge.Original;
const Modified = CodeMirrorMerge.Modified;
let doc = `one
two
three
four
five`;

export const Example = () => {
  return (
    <CodeMirrorMerge>
      <Original value={doc} />
      <Modified
        value={doc.replace(/t/g, 'T') + 'Six'}
        extensions={[EditorView.editable.of(false), EditorState.readOnly.of(true)]}
      />
    </CodeMirrorMerge>
  );
};

Support Hook

import { useEffect, useMemo, useRef } from 'react';
import { useCodeMirror } from '@uiw/react-codemirror';
import { javascript } from '@codemirror/lang-javascript';

const code = "console.log('hello world!');\n\n\n";
// Define the extensions outside the component for the best performance.
// If you need dynamic extensions, use React.useMemo to minimize reference changes
// which cause costly re-renders.
const extensions = [javascript()];

export default function App() {
  const editor = useRef();
  const { setContainer } = useCodeMirror({
    container: editor.current,
    extensions,
    value: code,
  });

  useEffect(() => {
    if (editor.current) {
      setContainer(editor.current);
    }
  }, [editor.current]);

  return <div ref={editor} />;
}

Using Theme

We have created a theme editor where you can define your own theme. We have also defined some themes ourselves, which can be installed and used directly. Below is a usage example:

import CodeMirror from '@uiw/react-codemirror';
import { javascript } from '@codemirror/lang-javascript';
import { okaidia } from '@uiw/codemirror-theme-okaidia';

const extensions = [javascript({ jsx: true })];

export default function App() {
  return (
    <CodeMirror
      value="console.log('hello world!');"
      height="200px"
      theme={okaidia}
      extensions={[javascript({ jsx: true })]}
    />
  );
}

Using custom theme

import CodeMirror from '@uiw/react-codemirror';
import { createTheme } from '@uiw/codemirror-themes';
import { javascript } from '@codemirror/lang-javascript';
import { tags as t } from '@lezer/highlight';

const myTheme = createTheme({
  theme: 'light',
  settings: {
    background: '#ffffff',
    foreground: '#75baff',
    caret: '#5d00ff',
    selection: '#036dd626',
    selectionMatch: '#036dd626',
    lineHighlight: '#8a91991a',
    gutterBackground: '#fff',
    gutterForeground: '#8a919966',
  },
  styles: [
    { tag: t.comment, color: '#787b8099' },
    { tag: t.variableName, color: '#0080ff' },
    { tag: [t.string, t.special(t.brace)], color: '#5c6166' },
    { tag: t.number, color: '#5c6166' },
    { tag: t.bool, color: '#5c6166' },
    { tag: t.null, color: '#5c6166' },
    { tag: t.keyword, color: '#5c6166' },
    { tag: t.operator, color: '#5c6166' },
    { tag: t.className, color: '#5c6166' },
    { tag: t.definition(t.typeName), color: '#5c6166' },
    { tag: t.typeName, color: '#5c6166' },
    { tag: t.angleBracket, color: '#5c6166' },
    { tag: t.tagName, color: '#5c6166' },
    { tag: t.attributeName, color: '#5c6166' },
  ],
});
const extensions = [javascript({ jsx: true })];

export default function App() {
  const onChange = React.useCallback((value, viewUpdate) => {
    console.log('value:', value);
  }, []);
  return (
    <CodeMirror
      value="console.log('hello world!');"
      height="200px"
      theme={myTheme}
      extensions={extensions}
      onChange={onChange}
    />
  );
}

Use initialState to restore state from JSON-serialized representation

CodeMirror allows to serialize editor state to JSON representation with toJSON function for persistency or other needs. This JSON representation can be later used to recreate ReactCodeMirror component with the same internal state.

For example, this is how undo history can be saved in the local storage, so that it remains after the page reloads

import CodeMirror from '@uiw/react-codemirror';
import { historyField } from '@codemirror/commands';

// When custom fields should be serialized, you can pass them in as an object mapping property names to fields.
// See [toJSON](https://codemirror.net/docs/ref/#state.EditorState.toJSON) documentation for more details
const stateFields = { history: historyField };

export function EditorWithInitialState() {
  const serializedState = localStorage.getItem('myEditorState');
  const value = localStorage.getItem('myValue') || '';

  return (
    <CodeMirror
      value={value}
      initialState={
        serializedState
          ? {
              json: JSON.parse(serializedState || ''),
              fields: stateFields,
            }
          : undefined
      }
      onChange={(value, viewUpdate) => {
        localStorage.setItem('myValue', value);

        const state = viewUpdate.state.toJSON(stateFields);
        localStorage.setItem('myEditorState', JSON.stringify(state));
      }}
    />
  );
}

Props

• value?: string value of the auto created model in the editor.
• width?: string width of editor. Defaults to auto.
• height?: string height of editor. Defaults to auto.
• theme?: 'light' / 'dark' / Extension Defaults to 'light'.

import React from 'react';
import { EditorState, EditorStateConfig, Extension } from '@codemirror/state';
import { EditorView, ViewUpdate } from '@codemirror/view';
export * from '@codemirror/view';
export * from '@codemirror/basic-setup';
export * from '@codemirror/state';
export interface UseCodeMirror extends ReactCodeMirrorProps {
  container?: HTMLDivElement | null;
}
export declare function useCodeMirror(props: UseCodeMirror): {
  state: EditorState | undefined;
  setState: import('react').Dispatch<import('react').SetStateAction<EditorState | undefined>>;
  view: EditorView | undefined;
  setView: import('react').Dispatch<import('react').SetStateAction<EditorView | undefined>>;
  container: HTMLDivElement | null | undefined;
  setContainer: import('react').Dispatch<import('react').SetStateAction<HTMLDivElement | null | undefined>>;
};
export interface ReactCodeMirrorProps
  extends Omit<EditorStateConfig, 'doc' | 'extensions'>,
    Omit<React.HTMLAttributes<HTMLDivElement>, 'onChange' | 'placeholder'> {
  /** value of the auto created model in the editor. */
  value?: string;
  height?: string;
  minHeight?: string;
  maxHeight?: string;
  width?: string;
  minWidth?: string;
  maxWidth?: string;
  /** focus on the editor. */
  autoFocus?: boolean;
  /** Enables a placeholder—a piece of example content to show when the editor is empty. */
  placeholder?: string | HTMLElement;
  /**
   * `light` / `dark` / `Extension` Defaults to `light`.
   * @default light
   */
  theme?: 'light' | 'dark' | Extension;
  /**
   * Whether to optional basicSetup by default
   * @default true
   */
  basicSetup?: boolean | BasicSetupOptions;
  /**
   * This disables editing of the editor content by the user.
   * @default true
   */
  editable?: boolean;
  /**
   * This disables editing of the editor content by the user.
   * @default false
   */
  readOnly?: boolean;
  /**
   * Controls whether pressing the `Tab` key inserts a tab character and indents the text (`true`)
   * or behaves according to the browser's default behavior (`false`).
   * @default true
   */
  indentWithTab?: boolean;
  /** Fired whenever a change occurs to the document. */
  onChange?(value: string, viewUpdate: ViewUpdate): void;
  /** Some data on the statistics editor. */
  onStatistics?(data: Statistics): void;
  /** The first time the editor executes the event. */
  onCreateEditor?(view: EditorView, state: EditorState): void;
  /** Fired whenever any state change occurs within the editor, including non-document changes like lint results. */
  onUpdate?(viewUpdate: ViewUpdate): void;
  /**
   * Extension values can be [provided](https://codemirror.net/6/docs/ref/#state.EditorStateConfig.extensions) when creating a state to attach various kinds of configuration and behavior information.
   * They can either be built-in extension-providing objects,
   * such as [state fields](https://codemirror.net/6/docs/ref/#state.StateField) or [facet providers](https://codemirror.net/6/docs/ref/#state.Facet.of),
   * or objects with an extension in its `extension` property. Extensions can be nested in arrays arbitrarily deep—they will be flattened when processed.
   */
  extensions?: Extension[];
  /**
   * If the view is going to be mounted in a shadow root or document other than the one held by the global variable document (the default), you should pass it here.
   * Originally from the [config of EditorView](https://codemirror.net/6/docs/ref/#view.EditorView.constructor%5Econfig.root)
   */
  root?: ShadowRoot | Document;
  /**
   * Create a state from its JSON representation serialized with [toJSON](https://codemirror.net/docs/ref/#state.EditorState.toJSON) function
   */
  initialState?: {
    json: any;
    fields?: Record<'string', StateField<any>>;
  };
}
export interface ReactCodeMirrorRef {
  editor?: HTMLDivElement | null;
  state?: EditorState;
  view?: EditorView;
}
declare const ReactCodeMirror: React.ForwardRefExoticComponent<
  ReactCodeMirrorProps & React.RefAttributes<ReactCodeMirrorRef>
>;
export default ReactCodeMirror;
export interface BasicSetupOptions {
  lineNumbers?: boolean;
  highlightActiveLineGutter?: boolean;
  highlightSpecialChars?: boolean;
  history?: boolean;
  foldGutter?: boolean;
  drawSelection?: boolean;
  dropCursor?: boolean;
  allowMultipleSelections?: boolean;
  indentOnInput?: boolean;
  syntaxHighlighting?: boolean;
  bracketMatching?: boolean;
  closeBrackets?: boolean;
  autocompletion?: boolean;
  rectangularSelection?: boolean;
  crosshairCursor?: boolean;
  highlightActiveLine?: boolean;
  highlightSelectionMatches?: boolean;
  closeBracketsKeymap?: boolean;
  defaultKeymap?: boolean;
  searchKeymap?: boolean;
  historyKeymap?: boolean;
  foldKeymap?: boolean;
  completionKeymap?: boolean;
  lintKeymap?: boolean;
}

import { EditorSelection, SelectionRange } from '@codemirror/state';
import { ViewUpdate } from '@codemirror/view';
export interface Statistics {
  /** Get the number of lines in the editor. */
  lineCount: number;
  /** total length of the document */
  length: number;
  /** Get the proper [line-break](https://codemirror.net/docs/ref/#state.EditorState^lineSeparator) string for this state. */
  lineBreak: string;
  /** Returns true when the editor is [configured](https://codemirror.net/6/docs/ref/#state.EditorState^readOnly) to be read-only. */
  readOnly: boolean;
  /** The size (in columns) of a tab in the document, determined by the [`tabSize`](https://codemirror.net/6/docs/ref/#state.EditorState^tabSize) facet. */
  tabSize: number;
  /** Cursor Position */
  selection: EditorSelection;
  /** Make sure the selection only has one range. */
  selectionAsSingle: SelectionRange;
  /** Retrieves a list of all current selections. */
  ranges: readonly SelectionRange[];
  /** Get the currently selected code. */
  selectionCode: string;
  /**
   * The length of the given array should be the same as the number of active selections.
   * Replaces the content of the selections with the strings in the array.
   */
  selections: string[];
  /** Return true if any text is selected. */
  selectedText: boolean;
}
export declare const getStatistics: (view: ViewUpdate) => Statistics;

Related

• @uiw/react-textarea-code-editor: A simple code editor with syntax highlighting.
• @uiw/react-md-editor: A simple markdown editor with preview, implemented with React.js and TypeScript.
• @uiw/react-monacoeditor: Monaco Editor component for React.
• @uiw/react-markdown-editor: A markdown editor with preview, implemented with React.js and TypeScript.
• @uiw/react-markdown-preview: React component preview markdown text in web browser.
• Online JSON Viewer Online JSON Viewer, JSON Beautifier to beautify and tree view of JSON data - It works as JSON Pretty Print to pretty print JSON data.

Contributors

As always, thanks to our amazing contributors!

Made with github-action-contributors.

License

Licensed under the MIT License.