Function withMemo

packages/runtime-core/src/helpers/withMemo.ts:4–21

(
  memo: any[],
  render: () => VNode<any, any>,
  cache: any[],
  index: number,
)

import { type VNode, currentBlock, isBlockTreeEnabled } from '../vnode'

export function withMemo(
  memo: any[],
  render: () => VNode<any, any>,
  cache: any[],
  index: number,
): VNode<any, any> {
  const cached = cache[index] as VNode | undefined
  if (cached && isMemoSame(cached, memo)) {
    return cached
  }
  const ret = render()

  // shallow clone
  ret.memo = memo.slice()
  ret.cacheIndex = index

  return (cache[index] = ret)
}

export function isMemoSame(cached: VNode, memo: any[]): boolean {
  const prev: any[] = cached.memo!