In Ionic application, we are integrating AWS-Amplify and we can able to insert and fetch the data. But while implementing subscription we are getting compiler error says

Prop,angular,amazon-web-services,ionic2,amazon-dynamodb,aws-amplify"/>

时间戳

首页 > 解决方案 > “承诺”类型上不存在属性“订阅”| 可观察的'

In Ionic application, we are integrating AWS-Amplify and we can able to insert and fetch the data. But while implementing subscription we are getting compiler error says

Prop

angular - “承诺”类型上不存在属性“订阅”| 可观察的'

In Ionic application, we are integrating AWS-Amplify and we can able to insert and fetch the data. But while implementing subscription we are getting compiler error says

Prop

问题描述

In Ionic application, we are integrating AWS-Amplify and we can able to insert and fetch the data. But while implementing subscription we are getting compiler error says

Property 'subscribe' does not exist on type 'Promise | Observable'. Property 'subscribe' does not exist on type 'Promise'.

In Subscription.ts 

export const onCreateEmployee = `subscription OnCreateEmployee(
  $employee_id: Int
  $employee_name: String
) {
  onCreateEmployee(
    employee_id: $employee_id
    employee_name: $employee_name
  ) {
    employee_id
    employee_name
  }
}

In Main.ts

const subscription = API.graphql(
      graphqlOperation(onCreateEmployee)
    ).subscribe((eventData) => { console.log(eventData)
    });

In main.ts, it shows the error like cannot subscribe ..... (see the above error).

Can anybody know how to resolve this?

Thanks

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标签： angularamazon-web-servicesionic2amazon-dynamodbaws-amplify

解决方案

由于结果API.graphql()可以是两者，Promise当您查询数据以立即返回或Observable订阅时，您需要告诉 TypeScript 会发生什么：

(API.graphql(
  graphqlOperation(onCreateEmployee)
) as unknown as Observable<YourEventDataType>)
.subscribe(
  (eventData) => { console.log(eventData) }
);

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