mergeVNodeHook() — vue Function Reference

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

Function typescript VueCore VDom calls 1

Entity Profile

VueCore→ VDom→ mergeVNodeHook() — vue Function Reference

Dependency Diagram

graph TD
  7a06e596_c3cd_223f_3edc_18572e0bd1f4["mergeVNodeHook()"]
  2fe22abf_9073_15d3_f856_f421b0fe047a["merge-hook.ts"]
  7a06e596_c3cd_223f_3edc_18572e0bd1f4 -->|defined in| 2fe22abf_9073_15d3_f856_f421b0fe047a
  d9d418b5_5caf_d879_89fa_46602272fa33["createFnInvoker()"]
  7a06e596_c3cd_223f_3edc_18572e0bd1f4 -->|calls| d9d418b5_5caf_d879_89fa_46602272fa33
  style 7a06e596_c3cd_223f_3edc_18572e0bd1f4 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
}