Method push

lib/handler_stack.js:29–34

(handler)

  // Adds a handler to the top of the stack. Returns a unique ID for that handler that can be used
  // to remove it later.
  push(handler) {
    handler.id = ++this.counter;
    if (!handler._name) handler._name = `anon-${handler.id}`;
    this.stack.push(handler);
    return handler.id = ++this.counter;
  }

  // As above, except the new handler is added to the bottom of the stack.
  unshift(handler) {