@vue/babel-plugin-transform-vue-jsx

What is @vue/babel-plugin-transform-vue-jsx?

@vue/babel-plugin-transform-vue-jsx is a Babel plugin that allows you to use JSX syntax in Vue.js applications. This plugin transforms JSX into Vue render functions, enabling a more React-like development experience within the Vue ecosystem.

What are @vue/babel-plugin-transform-vue-jsx's main functionalities?

Basic JSX Syntax

This feature allows you to write Vue components using JSX syntax, which can be more concise and readable compared to traditional Vue templates.

const MyComponent = { render() { return <div>Hello, JSX!</div>; } };

Using Props

You can easily pass props to your components using JSX, making it straightforward to manage dynamic data.

const MyComponent = { props: ['message'], render() { return <div>{this.message}</div>; } };

Event Handling

JSX syntax allows for inline event handling, making it easy to attach event listeners directly within your render functions.

const MyComponent = { render() { return <button onClick={() => alert('Clicked!')}>Click Me</button>; } };

Conditional Rendering

Conditional rendering in JSX is straightforward, allowing you to use JavaScript expressions to determine what gets rendered.

const MyComponent = { data() { return { isVisible: true }; }, render() { return this.isVisible ? <div>Visible</div> : <div>Hidden</div>; } };

Looping Through Data

JSX makes it easy to loop through arrays and render lists of elements, leveraging JavaScript's array methods.

const MyComponent = { data() { return { items: ['Item 1', 'Item 2', 'Item 3'] }; }, render() { return <ul>{this.items.map(item => <li>{item}</li>)}</ul>; } };

Other packages similar to @vue/babel-plugin-transform-vue-jsx

babel-plugin-transform-react-jsx

This Babel plugin transforms JSX syntax into React.createElement calls. It is primarily used in React projects and offers similar functionality to @vue/babel-plugin-transform-vue-jsx but is tailored for React instead of Vue.

vue-jsx

vue-jsx is another package that provides JSX support for Vue.js. It offers similar functionality to @vue/babel-plugin-transform-vue-jsx but may have different configuration options and performance characteristics.

babel-plugin-jsx-pragmatic

This plugin allows you to use JSX with any library by specifying a pragma. It is more flexible than @vue/babel-plugin-transform-vue-jsx but requires additional configuration to work with Vue.

README

@vue/babel-plugin-transform-vue-jsx

Babel plugin for Vue 2.0 JSX

Babel Compatibility Notes

• This repo is only compatible with Babel 7.x, for 6.x please use vuejs/babel-plugin-transform-vue-jsx

Requirements

• Assumes you are using Babel with a module bundler e.g. Webpack, because the spread merge helper is imported as a module to avoid duplication.

• This is mutually exclusive with babel-plugin-transform-react-jsx.

Usage

npm install @vue/babel-plugin-transform-vue-jsx --save-dev
npm install @vue/babel-helper-vue-jsx-merge-props --save

In your .babelrc:

{
  "plugins": ["transform-vue-jsx"]
}

However it is recommended to use the configurable preset instead.

Details

The plugin transpiles the following JSX:

<div id="foo">{this.text}</div>

To the following JavaScript:

h(
  'div',
  {
    attrs: {
      id: 'foo',
    },
  },
  [this.text],
)

Note the h function, which is a shorthand for a Vue instance's $createElement method, must be in the scope where the JSX is. Since this method is passed to component render functions as the first argument, in most cases you'd do this:

Vue.component('jsx-example', {
  render(h) {
    // <-- h must be in scope
    return <div id="foo">bar</div>
  },
})

Difference from React JSX

First, Vue 2.0's vnode format is different from React's. The second argument to the createElement call is a "data object" that accepts nested objects. Each nested object will be then processed by corresponding modules:

render (h) {
  return h('div', {
    // Component props
    props: {
      msg: 'hi'
    },
    // Normal HTML attributes
    attrs: {
      id: 'foo'
    },
    // DOM props
    domProps: {
      innerHTML: 'bar'
    },
    // Event handlers are nested under "on", though
    // modifiers such as in v-on:keyup.enter are not
    // supported. You'll have to manually check the
    // keyCode in the handler instead.
    on: {
      click: this.clickHandler
    },
    // For components only. Allows you to listen to
    // native events, rather than events emitted from
    // the component using vm.$emit.
    nativeOn: {
      click: this.nativeClickHandler
    },
    // Class is a special module, same API as `v-bind:class`
    class: {
      foo: true,
      bar: false
    },
    // Style is also same as `v-bind:style`
    style: {
      color: 'red',
      fontSize: '14px'
    },
    // Other special top-level properties
    key: 'key',
    ref: 'ref',
    // Assign the `ref` is used on elements/components with v-for
    refInFor: true,
    slot: 'slot'
  })
}

The equivalent of the above in Vue 2.0 JSX is:

render (h) {
  return (
    <div
      // Component props
      propsMsg="hi"
      // Normal attributes or component props.
      id="foo"
      // DOM properties are prefixed with `domProps`
      domPropsInnerHTML="bar"
      // event listeners are prefixed with `on` or `nativeOn`
      onClick={this.clickHandler}
      nativeOnClick={this.nativeClickHandler}
      // other special top-level properties
      class={{ foo: true, bar: false }}
      style={{ color: 'red', fontSize: '14px' }}
      key="key"
      ref="ref"
      // assign the `ref` is used on elements/components with v-for
      refInFor
      slot="slot">
    </div>
  )
}

Component Tip

If a custom element starts with lowercase, it will be treated as a string id and used to lookup a registered component. If it starts with uppercase, it will be treated as an identifier, which allows you to do:

import Todo from './Todo.js'

export default {
  render(h) {
    return <Todo /> // no need to register Todo via components option
  },
}

JSX Spread

JSX spread is supported, and this plugin will intelligently merge nested data properties. For example:

const data = {
  class: ['b', 'c'],
}
const vnode = <div class="a" {...data} />

The merged data will be:

{ class: ['a', 'b', 'c'] }

Vue directives

Vue directives are usable the same way as in template with a few key differences:

• You can use directives camelCased instead of kebab-cased (vMyDirective is treated as v-my-directive)
• You have to use underscore sign instead of dots for modifiers because of JSXIdentifier limitation.
• Only runtime directives work (only v-show and custom directives), compile-time directives are out of this project's scope.

A full example would be: <MyComponent vMyDirective:argument_modifier1_modifier2={someExpression} />