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    2.0.4 • Public • Published


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    An extensible library to highlight (and comment) JSX syntax in the Monaco Editor using Babel. It exposes its AST after it does its magic, so you can add your own syntax-based or custom highlights.


    Monaco JSX Highlighter demo

    # with npm (assuming you are already using monaco-editor)
      npm i @babel/parser @babel/traverse monaco-jsx-highlighter
    # with yarn (assuming you are already using monaco-editor)
      yarn add @babel/parser @babel/traverse monaco-jsx-highlighter


    import monaco from 'monaco-editor';
    import {parse} from "@babel/parser";
    import traverse from "@babel/traverse";
    import MonacoJSXHighlighter from 'monaco-jsx-highlighter';
    // Instantiate the highlighter
    const monacoJSXHighlighter = new MonacoJSXHighlighter(
       monaco, babel, traverse, aMonacoEditor()
    // Activate highlighting (debounceTime default: 100ms)
    // Activate JSX commenting
    // Done =)
    function aMonacoEditor() {
       return monaco.editor.create(
          document.getElementById("editor"), {
             value: 'const AB=<A x={d}><B>{"hello"}</B></A>;',
             language: 'javascript'


    New in v2.x

    • Minified versions are now <12kB (cjs, es, umd).
    • Normal versions are ES2018 compliant.
    • Polyfilled versions (>2.0.2-polyfilled) are available for node users below 8.6, they target node 0.
    • Refactored and commented code for those who want to use the highlighting or commenting APIs separately.
    • All utils and core API are exposed.
    • Several defect repairs (no console log pollution or highlight breaking on code changes).

    Breaking Changes

    • configureLocToMonacoRange has been renamed to configureLoc2Range.
    • afterHighlight returns an object containing the ast instead of the ast object:
    - afterHighlight(ast)
    + afterHighlight({ast,})

    New in v1.x

    • Babel is now used directly instead of via JsCodeShift.
    • React fragment, spread child, spread attribute, and container expression highlighting.
    • highlightOnDidChangeModelContent(debounceTime) method debounces highlight updates.
    • Several defect repairs.

    Breaking Changes

    If you have used 0.x versions, you'll notice JsCodeShift has been replaced with Babel:

    - import j from 'jscodeshift';
    + import {parse} from "@babel/parser";
    + import traverse from "@babel/traverse";

    This only affects the constructor signature:

    + const babelParse = code => parse(code, {sourceType: "module", plugins: ["jsx"],  errorRecovery: true,});
     const monacoJSXHighlighter = new MonacoJSXHighlighter(
    - j,
    + babelParse, traverse,

    Also, monacoJSXHighlighter.highlightOnDidChangeModelContent method now has an optional debounce time as first parameter on its signature:

    - afterHighlight: func,
    + debounceTime: number, afterHighlight: func,


    It requires monaco-editor , @babel/parser and @babel/traverse, for convenience, they are listed as peer dependencies and passed by reference (so you can do lazy loading). Please install them before monaco-jsx-highlighter;


    Install the package in your project directory with:


    # with npm
     npm install @babel/parser
     npm install @babel/traverse
     npm install monaco-jsx-highlighter


    # with yarn
     yarn add @babel/parser
     yarn add @babel/traverse
     yarn add monaco-jsx-highlighter

    Advanced Usage

    After your have a Monaco JSX Highlighter instance, monacoJSXHighlighter:

    const defaultOptions = {
       parser: 'babel', // for reference only, only babel is supported right now
       isHighlightGlyph: false, // if JSX elements should decorate the line number gutter
       iShowHover: false, // if JSX types should  tooltip with their type info
       isUseSeparateElementStyles: false, // if opening elements and closing elements have different styling
       // you can pass your own custom APIs, check core/ and uitls/ for more details
       monacoEditorManager: null,
       decoratorMapper: null,
       jsxCommenter: null,
    const monacoJSXHighlighter = new MonacoJSXHighlighter(
       monaco, babelParse, traverse, monacoEditor, defaultOptions

    The highlight activation method, monacoJSXHighlighter.highlightOnDidChangeModelContent(debounceTime: number, afterHighlight: func, ...) , accepts a callback among other parameters. The callback afterHighlight passes the AST used to highlight the code as well other inner objects. Passing parameters and using the disposer function returned by the call are optional.

    Note: The disposer is always called when the editor is disposed.

    // Optional: Disable highlighting when needed (e.g. toggling, unmounting, pausing)
    const highlighterDisposeFunc = monacoJSXHighlighter.highlightOnDidChangeModelContent(
       ast => {}
    highlighterDisposeFunc(); // if you need to
    // Internally the highlighter is triggering after each code change debounced
    let tid = null;
    let debounceTime = 100; // default
    monacoEditor.onDidChangeModelContent(() => {
       tid = setTimeout(() => {
    // You can do the higlighting directly at anytime
    // or customize its behavior by adding custom highlighting after the JSX highlighting
    const afterHighlight = (
          ast, // the ast generate by  Babel
    ) => {
       //... your customization code, check Babel for more info about AST types
    monacoJSXHighlighter.highlightCode( // defaults
       afterHighlight, // ast => ast,
       onHighlightError, // error => error,
       getAstPromise, // this.getAstPromise,
       onGetAstErrors, // error => error,

    Replacing CSS classes with your own

    import {JSXTypes} from 'monaco-jsx-highlighter';
    // JSXTypes:JSX Syntax types and their CSS classnames.
    // Customize the color font in JSX texts:  .myCustomCSS {color: red;}
    JSXTypes.JSXText.options.inlineClassName = "myCustomCSS";

    Overriding CSS classes

    Take a look of the src/JSXColoringProvider.css file and override the CSS classes you need. Make sure to import your customization CSS files after you import monaco-jsx-highlighter.

    JSX Commenting

    Additionally, you can add JSX commenting to your monaco editor with monacoJSXHighlighter.addJSXCommentCommand(): comments in JSX children will result in {/*...*/} instead of //.... It mimics the commenting behavior of the WebStorm IDE.

    Follow this code to find out other perks:

    // Optional: Disable JSX commenting when needed (e.g. toggling, unmounting, pausing)
    const commentDisposeFunc = monacoJSXHighlighter.addJSXCommentCommand();
    commentDisposeFunc(); // if you need to

    Standalone JSX Commenting

    If you only need the commenting feature, try this:

    import {makeJSXCommenterBundle} from 'monaco-jsx-highlighter';
    const [
       jsxCommenter, monacoEditorManager,
       parseJSXExpressionsPromise, getAstPromise,
       loc2Range, range2Loc
    ] = makeJSXCommenterBundle(
       monaco, parse, traverse, monacoEditor,
    const commentDisposeFunc = jsxCommenter.addJSXCommentCommand();
    commentDisposeFunc(); // if you need to

    Works same as before, all other objects are exposed if you need them.

    Creating Monaco compatible ranges from Babel

    import {configureLoc2Range} from 'monaco-jsx-highlighter';
    // configureLoc2Range: converts Babel locations to Monaco Ranges
    const loc2Range = configureLoc2Range(monaco);
    const monacoRange = loc2Range(babelAstNode.loc);


    If you are using Next.js or @monaco-editor/react, and you get this error:

    ReferenceError: document is not defined

    In the case of @monaco-editor/react, probably you are instantiating the highlighter before Monaco has finished setting up. Check out the live demo for more details.

    For Next.js, perhaps the library is not instantiated in the browser, try:

    import dynamic from "next/dynamic";
    let jsxHighlighter = null;
    const HighlighterComponent = dynamic(() => {
       import("monaco-jsx-highlighter").then((allMonacoSyntaxHighlighter) => {
          jsxHighlighter = allMonacoSyntaxHighlighter.default;
       return null;
    }, {ssr: false});


    npm i monaco-jsx-highlighter

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    • luminaxster