Vue JSX Uses HTML Attributes Not React Conventions

Impact: MEDIUM - Vue's JSX transform uses standard HTML attribute names (class, for) instead of React's JavaScript-friendly names (className, htmlFor). With proper TypeScript configuration, using React conventions like className or htmlFor will produce TypeScript errors, which is good for catching these inconsistencies early. Note that Vue's runtime is lenient and will actually convert these attributes correctly, but using HTML attributes is the recommended practice for consistency with Vue templates and proper type safety.

When writing JSX in Vue, use the same attribute names you would use in regular HTML templates. This is a fundamental difference from React's JSX where class and for are reserved JavaScript keywords.

Task Checklist

Use class instead of className in Vue JSX
Use for instead of htmlFor in Vue JSX
Use standard HTML event names with on prefix (onClick, onInput)
When migrating React components to Vue, update all attribute names
Configure TypeScript properly for Vue JSX type inference

Incorrect (React-style):

// AVOID: React conventions cause TypeScript errors in Vue JSX
// (Vue runtime is lenient and converts these, but types don't allow them)
export default {
  setup() {
    return () => (
      <div className="container">
        <label htmlFor="email">Email:</label>
        <input id="email" className="input-field" />
      </div>
    )
  }
}

// AVOID: TypeScript will reject className/htmlFor with Vue's JSX types
const Button = () => (
  <button
    className="btn btn-primary"  // TS error: Property 'className' does not exist
    htmlFor="form"               // TS error: Property 'htmlFor' does not exist
  >
    Submit
  </button>
)

Correct (Vue-style):

// CORRECT: Use standard HTML attributes
export default {
  setup() {
    return () => (
      <div class="container">
        <label for="email">Email:</label>
        <input id="email" class="input-field" />
      </div>
    )
  }
}

// CORRECT: Vue TSX with HTML attributes
const Button = () => (
  <button
    class="btn btn-primary"
  >
    Submit
  </button>
)

TypeScript Configuration for Vue JSX

To enable proper type inference and IntelliSense for Vue JSX/TSX, configure your tsconfig.json:

{
  "compilerOptions": {
    "jsx": "preserve",
    "jsxImportSource": "vue"
  }
}

Starting from Vue 3.4, Vue no longer implicitly registers the global JSX namespace, so jsxImportSource is required for TypeScript to use Vue's JSX type definitions.

Vite Configuration

For Vite projects, ensure you have the JSX plugin configured in vite.config.ts:

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import vueJsx from '@vitejs/plugin-vue-jsx'

export default defineConfig({
  plugins: [vue(), vueJsx()]
})

Other Attribute Differences

React JSX	Vue JSX	HTML
className	class	class
htmlFor	for	for
onChange	onInput (for live updates)	oninput
tabIndex	tabindex	tabindex
readOnly	readonly	readonly

Event Handling in Vue JSX

// Vue JSX event handling
export default {
  setup() {
    const handleClick = () => console.log('clicked')
    const handleInput = (e) => console.log(e.target.value)

    return () => (
      <div>
        <button onClick={handleClick}>Click</button>
        <input onInput={handleInput} />

        {/* Event modifiers via helper */}
        <div onClick={withModifiers(handleClick, ['self'])}>
          Only triggers on self
        </div>
      </div>
    )
  }
}

Reference

Vue.js JSX and TSX

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