Render Function APIs #

h() #

Creates virtual DOM nodes (vnodes).

• Тип:

  ts

  // full signature
  function h(
    type: string | Component,
    props?: object | null,
    children?: Children | Slot | Slots
  ): VNode
  
  // omitting props
  function h(type: string | Component, children?: Children | Slot): VNode
  
  type Children = string | number | boolean | VNode | null | Children[]
  
  type Slot = () => Children
  
  type Slots = { [name: string]: Slot }
  

  Types are simplified for readability.

• Подробности:

  The first argument can either be a string (for native elements) or a Vue component definition. The second argument is the props to be passed, and the third argument is the children.

  When creating a component vnode, the children must be passed as slot functions. A single slot function can be passed if the component expects only the default slot. Otherwise, the slots must be passed as an object of slot functions.

  For convenience, the props argument can be omitted when the children is not a slots object.

• Пример:

  Creating native elements:

  js

  import { h } from 'vue'
  
  // all arguments except the type are optional
  h('div')
  h('div', { id: 'foo' })
  
  // both attributes and properties can be used in props
  // Vue automatically picks the right way to assign it
  h('div', { class: 'bar', innerHTML: 'hello' })
  
  // class and style have the same object / array
  // value support like in templates
  h('div', { class: [foo, { bar }], style: { color: 'red' } })
  
  // event listeners should be passed as onXxx
  h('div', { onClick: () => {} })
  
  // children can be a string
  h('div', { id: 'foo' }, 'hello')
  
  // props can be omitted when there are no props
  h('div', 'hello')
  h('div', [h('span', 'hello')])
  
  // children array can contain mixed vnodes and strings
  h('div', ['hello', h('span', 'hello')])
  

  Creating components:

  js

  import Foo from './Foo.vue'
  
  // passing props
  h(Foo, {
    // equivalent of some-prop="hello"
    someProp: 'hello',
    // equivalent of @update="() => {}"
    onUpdate: () => {}
  })
  
  // passing single default slot
  h(Foo, () => 'default slot')
  
  // passing named slots
  // notice the `null` is required to avoid
  // slots object being treated as props
  h(MyComponent, null, {
    default: () => 'default slot',
    foo: () => h('div', 'foo'),
    bar: () => [h('span', 'one'), h('span', 'two')]
  })
  

• См. также: Guide - Render Functions - Creating VNodes

mergeProps() #

Merge multiple props objects with special handling for certain props.

• Тип:

  ts

  function mergeProps(...args: object[]): object
  

• Подробности:

  mergeProps() supports merging multiple props objects with special handling for the following props:

  • class
  • style
  • onXxx event listeners - multiple listeners with the same name will be merged into an array.

  If you do not need the merge behavior and want simple overwrites, native object spread can be used instead.

• Пример:

  js

  import { mergeProps } from 'vue'
  
  const one = {
    class: 'foo',
    onClick: handlerA
  }
  
  const two = {
    class: { bar: true },
    onClick: handlerB
  }
  
  const merged = mergeProps(one, two)
  /**
   {
     class: 'foo bar',
     onClick: [handlerA, handlerB]
   }
   */
  

cloneVNode() #

Clones a vnode.

• Тип:

  ts

  function cloneVNode(vnode: VNode, extraProps?: object): VNode
  

• Подробности:

  Returns a cloned vnode, optionally with extra props to merge with the original.

  Vnodes should be considered immutable once created, and you should not mutate the props of an existing vnode. Instead, clone it with different / extra props.

  Vnodes have special internal properties, so cloning them is not as simple as an object spread. cloneVNode() handles most of the internal logic.

• Пример:

  js

  import { h, cloneVNode } from 'vue'
  
  const original = h('div')
  const cloned = cloneVNode(original, { id: 'foo' })
  

isVNode() #

Checks if a value is a vnode.

• Тип:

  ts

  function isVNode(value: unknown): boolean
  

resolveComponent() #

For manually resolving a registered component by name.

• Тип:

  ts

  function resolveComponent(name: string): Component | string
  

• Подробности:

  Note: you do not need this if you can import the component directly.

  resolveComponent() must be called inside either setup() or the render function in order to resolve from the correct component context.

  If the component is not found, a runtime warning will be emitted, and the name string is returned.

• Пример:

  js

  const { h, resolveComponent } = Vue
  
  export default {
    setup() {
      const ButtonCounter = resolveComponent('ButtonCounter')
  
      return () => {
        return h(ButtonCounter)
      }
    }
  }
  

  js

  const { h, resolveComponent } = Vue
  
  export default {
    render() {
      const ButtonCounter = resolveComponent('ButtonCounter')
      return h(ButtonCounter)
    }
  }
  

• См. также: Guide - Render Functions - Components

resolveDirective() #

For manually resolving a registered directive by name.

• Тип:

  ts

  function resolveDirective(name: string): Directive | undefined
  

• Подробности:

  Note: you do not need this if you can import the component directly.

  resolveDirective() must be called inside either setup() or the render function in order to resolve from the correct component context.

  If the directive is not found, a runtime warning will be emitted, and the function returns undefined.

• См. также: Guide - Render Functions - Custom Directives

withDirectives() #

For adding custom directives to vnodes.

• Тип:

  ts

  function withDirectives(
    vnode: VNode,
    directives: DirectiveArguments
  ): VNode
  
  // [Directive, value, argument, modifiers]
  type DirectiveArguments = Array<
    | [Directive]
    | [Directive, any]
    | [Directive, any, string]
    | [Directive, any, string, DirectiveModifiers]
  >
  

• Подробности:

  Wraps an existing vnode with custom directives. The second argument is an array of custom directives. Each custom directive is also represented as an array in the form of [Directive, value, argument, modifiers]. Tailing elements of the array can be omitted if not needed.

• Пример:

  js

  import { h, withDirectives } from 'vue'
  
  // a custom directive
  const pin = {
    mounted() {
      /* ... */
    },
    updated() {
      /* ... */
    }
  }
  
  // <div v-pin:top.animate="200"></div>
  const vnode = withDirectives(h('div'), [
    [pin, 200, 'top', { animate: true }]
  ])
  

• См. также: Guide - Render Functions - Custom Directives

withModifiers() #

For adding built-in v-on modifiers to an event handler function.

• Тип:

  ts

  function withModifiers(fn: Function, modifiers: string[]): Function
  

• Пример:

  js

  import { h, withModifiers } from 'vue'
  
  const vnode = h('button', {
    // equivalent of v-on.stop.prevent
    onClick: withModifiers(() => {
      // ...
    }, ['stop', 'prevent'])
  })
  

• См. также: Guide - Render Functions - Event Modifiers