vue3-yuanma/packages/runtime-core/src/helpers/renderSlot.ts

import { Data } from '../component'
import { Slot } from '../componentSlots'
import {
  VNodeChildren,
  openBlock,
  createBlock,
  Fragment,
  VNode
} from '../vnode'
import { PatchFlags } from '@vue/shared'

export function renderSlot(
  slots: Record<string, Slot>,
  name: string,
  props: Data = {},
  // this is not a user-facing function, so the fallback is always generated by
  // the compiler and guaranteed to be an array
  fallback?: VNodeChildren
): VNode {
  const slot = slots[name]
  return (
    openBlock(),
    createBlock(
      Fragment,
      { key: props.key },
      slot ? slot(props) : fallback || [],
      slots._compiled ? 0 : PatchFlags.BAIL
    )
  )
}