@harnessa-fe/react-jsx

Drop-in JSX runtime that adds data-morphix-loc to every rendered DOM element in dev mode. Zero bundler plugins; one line in tsconfig.json makes it work everywhere — Next.js, Vite, Webpack, Remix, Astro, anywhere that respects the standard jsxImportSource compiler option.

This is the simpler, framework-agnostic alternative to @harnessa-fe/vite / @harnessa-fe/webpack. It works by wrapping React's jsxDEV() to read the source-location info React already passes through ({ fileName, lineNumber, columnNumber }) and stamp it onto the rendered element as a data-morphix-loc HTML attribute. The Harnessa-FE agent uses that attribute to map any DOM node back to its source file with project_where_is / project_source.

Install

pnpm add -D @harnessa-fe/react-jsx

Configure

// tsconfig.json
{
    "compilerOptions": {
        "jsxImportSource": "@harnessa-fe/react-jsx"
    }
}

That's it. Run pnpm dev and every <div> / <button> / etc. now has a data-morphix-loc="src/Foo.tsx:42:8" attribute in DEV builds.

What gets tagged

• ✅ Every host element (lowercase tag like div, button, input)
• ❌ React components (<Foo />) — but their rendered host elements ARE tagged, so <Foo /> containing a <div> puts the loc on the div
• ❌ data-morphix-loc attributes are stripped automatically in production builds (React uses jsx not jsxDEV there, and our jsx-runtime is a stock re-export)

How it works

When TypeScript / SWC / Babel see your JSX <div className="x" />, they transform it to:

jsxDEV('div', { className: 'x' }, undefined, false,
       { fileName: 'src/App.tsx', lineNumber: 42, columnNumber: 8 },
       this);

The source (5th argument) is provided by React 17+ JSX runtime as standard. We just intercept it and inject the location string as a DOM attribute:

jsxDEV('div', { className: 'x', 'data-morphix-loc': 'src/App.tsx:42:8' }, ...)

No bundler plugin needed because jsxImportSource is a first-class TS/SWC/Babel compiler option — it tells the compiler to import jsx* from your package instead of from react.

Compatibility

| Framework | Status | Notes | |---|---|---| | Next.js 13+ (App Router + Pages Router) | ✅ | webpack and Turbopack both honor jsxImportSource | | Vite + React | ✅ | reads from tsconfig automatically | | Webpack 5 + React | ✅ | works via babel or swc loader | | Remix / Astro / others | ✅ | any toolchain with standard JSX transform | | React Native | not tested | should work in theory | | React 17 / 18 / 19 | ✅ | jsxDEV signature stable across all three |

When NOT to use this

• Vue / Svelte projects — they don't use React's JSX runtime; use @harnessa-fe/vite or @harnessa-fe/webpack instead.
• Projects that need data-morphix-comp (component name) attributes — this runtime only emits data-morphix-loc. Component-name attributes still require the build-time transform.

License

MIT