I am facing restrictions in TypeScript when trying to modify RX JS responses

Question

I am facing restrictions in TypeScript when trying to modify RX JS responses

Can someone help me with a quick solution to this Angular 4 issue?

 title:string;
 content: string;
 comment: string;

 constructor( private http: HttpClient) {}

 posts: {title: string, content: string, comments: String[]}[] = [];

 ngOnInit() {
   this.http.get('http://localhost:3003/posts').subscribe( res => {
     console.log(res))
     // can't do res.forEach (object has no forEach)
     // can't do JSON.parse(res) because res is not a string

 })
}

The response content:

["{"title":"sadsa","content":"sadasd","comments":[]}", "{"title":"sadsa","content":"sadasd","comments":[]}", "{"title":"sadsa","content":"sadasd","comments":[]}", "{"title":"sadsa","content":"sadasd","comments":[]}", "{"title":"sadsa","content":"sadasd","comments":[]}", "{"title":"sadsa","content":"sadasd","comments":[]}", "{"title":"sadsa","content":"sadasd","comments":[]}"]

I am trying to handle an array received from the server that matches the client-side array, but it is coming in a stringified format. TypeScript is not recognizing it as an array and claims it to be an object. I also attempted sending an object containing the array, but encountered an 'unresolved variable' error. What could be missing in my approach?

angular typescript rxjs

Answer 1

Answer №1

This particular reply falls under the category of Response. By utilizing res.json(), you can access its contents. Interestingly, this information is not included in the official documentation as it seems Google has opted to keep you on your toes.

Answer 2

This particular reply falls under the category of Response. By utilizing res.json(), you can access its contents. Interestingly, this information is not included in the official documentation as it seems Google has opted to keep you on your toes.

Answer 3

Answer №2

With Angular's Http module, you have the ability to manipulate the response data before subscribing to the request. Here's an example:

...
ngOnInit() {
   this.http.get('http://localhost:3003/posts')
       .map(toJsonFn)  // or map to your own class or whatever you need
       .subscribe( res => {
           console.log(res))
       })
}

toJsonFn(res: Response){
    return res.json();
}
...

Keep in mind that you might need to import the map operator from rxjx - using import 'rxjs/add/operator/map'

It's worth noting that if you are using Angular 5's HttpClient, the response will automatically be parsed as json for you.

Answer 4

With Angular's Http module, you have the ability to manipulate the response data before subscribing to the request. Here's an example:

...
ngOnInit() {
   this.http.get('http://localhost:3003/posts')
       .map(toJsonFn)  // or map to your own class or whatever you need
       .subscribe( res => {
           console.log(res))
       })
}

toJsonFn(res: Response){
    return res.json();
}
...

Keep in mind that you might need to import the map operator from rxjx - using import 'rxjs/add/operator/map'

It's worth noting that if you are using Angular 5's HttpClient, the response will automatically be parsed as json for you.

Answer 5

Answer №3

Your input is not formatted correctly as a JSON object. Utilize the code snippet below to ensure proper JSON structure:

 ngOnInit() {
    this.http.get('http://localhost:3003/posts').subscribe( (res: any[]) => {
      console.log(res))
      let data = res.map(d => {
        return JSON.parse(d);
      });
      // data will be an array of data. Assign it to a component property.

    })
  }

This solution should address your issue.

Answer 6

Your input is not formatted correctly as a JSON object. Utilize the code snippet below to ensure proper JSON structure:

 ngOnInit() {
    this.http.get('http://localhost:3003/posts').subscribe( (res: any[]) => {
      console.log(res))
      let data = res.map(d => {
        return JSON.parse(d);
      });
      // data will be an array of data. Assign it to a component property.

    })
  }

This solution should address your issue.

I am facing restrictions in TypeScript when trying to modify RX JS responses

Answer №1

Answer №2

Answer №3

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