Gtag命令被忽略。跟踪器上已需要插件“ ec”

Question

我使用gtag库编写代码来跟踪增强型电子商务。当页面加载时，点击“添加到购物车”按钮后，我发送了add_to_cart事件，从而发送了产品点击印象。但这给了我这个错误

analytics_debug.js:23 Command ignored. Plugin "ec" has already been required on tracker。

这是我的代码

gtag("event", "add_to_cart", {
              "items": [
                {
                  "id": "2",
                  "name": "Hoodie",
                  "category": "cloth",
                  "quantity": "2",
                  "price": "16"
                }
              ]
            });