Function patchMethod

packages/zone.js/lib/common/utils.ts:424–461

(
  target: any,
  name: string,
  patchFn: (
    delegate: Function,
    delegateName: string,
    name: string,
  ) => (self: any, args: any[]) => any,
)

}

export function patchMethod(
  target: any,
  name: string,
  patchFn: (
    delegate: Function,
    delegateName: string,
    name: string,
  ) => (self: any, args: any[]) => any,
): Function | null {
  let proto = target;
  while (proto && !proto.hasOwnProperty(name)) {
    proto = ObjectGetPrototypeOf(proto);
  }
  if (!proto && target[name]) {
    // somehow we did not find it, but we can see it. This happens on IE for Window properties.
    proto = target;
  }

  const delegateName = zoneSymbol(name);
  let delegate: Function | null = null;
  if (proto && (!(delegate = proto[delegateName]) || !proto.hasOwnProperty(delegateName))) {
    delegate = proto[delegateName] = proto[name];
    // check whether proto[name] is writable
    // some property is readonly in safari, such as HtmlCanvasElement.prototype.toBlob
    const desc = proto && ObjectGetOwnPropertyDescriptor(proto, name);
    if (isPropertyWritable(desc)) {
      const patchDelegate = patchFn(delegate!, delegateName, name);
      proto[name] = function () {
        return patchDelegate(this, arguments as any);
      };
      attachOriginToPatched(proto[name], delegate);
      if (shouldCopySymbolProperties) {
        copySymbolProperties(delegate, proto[name]);
      }
    }
  }
  return delegate;
}

export interface MacroTaskMeta extends TaskData {
  name: string;