mergeVNodeHook() — vue Function Reference

Architecture documentation for the mergeVNodeHook() function in merge-hook.ts from the vue codebase.

Function typescript CoreRuntime VirtualDOM calls 1

Entity Profile

CoreRuntime→ VirtualDOM→ mergeVNodeHook() — vue Function Reference

Dependency Diagram

graph TD
  fd00fd89_3211_0406_304e_cf5129fb070b["mergeVNodeHook()"]
  1d9d4118_665c_f6c2_cd3e_e1c7a7b6e252["merge-hook.ts"]
  fd00fd89_3211_0406_304e_cf5129fb070b -->|defined in| 1d9d4118_665c_f6c2_cd3e_e1c7a7b6e252
  72dc3fd8_ab45_fab8_4ee3_ade3f6e39143["createFnInvoker()"]
  fd00fd89_3211_0406_304e_cf5129fb070b -->|calls| 72dc3fd8_ab45_fab8_4ee3_ade3f6e39143
  style fd00fd89_3211_0406_304e_cf5129fb070b fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

src/core/vdom/helpers/merge-hook.ts lines 5–40

export function mergeVNodeHook(
  def: Record<string, any>,
  hookKey: string,
  hook: Function
) {
  if (def instanceof VNode) {
    def = def.data!.hook || (def.data!.hook = {})
  }
  let invoker
  const oldHook = def[hookKey]

  function wrappedHook() {
    hook.apply(this, arguments)
    // important: remove merged hook to ensure it's called only once
    // and prevent memory leak
    remove(invoker.fns, wrappedHook)
  }

  if (isUndef(oldHook)) {
    // no existing hook
    invoker = createFnInvoker([wrappedHook])
  } else {
    /* istanbul ignore if */
    if (isDef(oldHook.fns) && isTrue(oldHook.merged)) {
      // already a merged invoker
      invoker = oldHook
      invoker.fns.push(wrappedHook)
    } else {
      // existing plain hook
      invoker = createFnInvoker([oldHook, wrappedHook])
    }
  }

  invoker.merged = true
  def[hookKey] = invoker
}