Function wrappedHook

static/vuejs/vue.esm.js:1706–1711

()

  var 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 (!oldHook) {
    // no existing hook