vuejs@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 --saveIn 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} />