放大未捕获的 AppSync 订阅（承诺中）答案

【问题标题】：Amplify AppSync Subscription Uncaught (in promise)放大未捕获的 AppSync 订阅（承诺中）
【发布时间】：2021-03-03 18:35:19
【问题描述】：

我正在尝试使用 AWS 放大 GraphQL 订阅，如下所示，

import Amplify,{ API, Storage, graphqlOperation } from "aws-amplify";
import awsmobile from "../../aws-exports";
Amplify.configure(awsmobile);
...
     const notiSubscription = API.graphql(graphqlOperation(onCreateNotification)).subscribe({
      next: (todoData) => {
        console.log(todoData);
      },
    });
...

onCreateNotification Graphql 是，

 subscription OnCreateNotification {
onCreateNotification {
  id
}}

以下是我得到的错误，

AWSAppSyncProvider.ts:204 Uncaught (in promise) undefined

rejected    @   AWSAppSyncProvider.ts:204
Promise.then (async)        
step    @   AWSAppSyncProvider.ts:204
(anonymous) @   AWSAppSyncProvider.ts:204
push../node_modules/@aws-amplify/pubsub/lib-esm/Providers/AWSAppSyncRealTimeProvider.js.__awaiter   @   AWSAppSyncProvider.ts:204
AWSAppSyncRealTimeProvider._startSubscriptionWithAWSAppSyncRealTime @   AWSAppSyncRealTimeProvider.ts:227
(anonymous) @   AWSAppSyncRealTimeProvider.ts:185
Subscription    @   Observable.js:197
subscribe   @   Observable.js:279
(anonymous) @   PubSub.ts:171
...

请帮帮我，我的配置也是

"aws_project_region": "us-east-1",
    "aws_appsync_graphqlEndpoint": "https://xxx.appsync-api.us-east-1.amazonaws.com/graphql",
    "aws_appsync_region": "us-east-1",
    "aws_appsync_authenticationType": "AMAZON_COGNITO_USER_POOLS",
    "aws_appsync_apiKey": "xxxx",

【问题讨论】：

标签： javascript reactjs graphql aws-amplify aws-appsync

【解决方案1】：

您需要在 useEffect() 挂钩中初始化订阅，然后取消订阅。

 useEffect(() => {
    const subscription = API.graphql(graphqlOperation(onCreateNotification))
      .subscribe({
        next: todoData => {
        console.log(todoData);
        }
      })
      return () => subscription.unsubscribe()
  }, [])

【讨论】：