CODEWITHSUNDEEP
angulartypescript
user3345721
user3345721

Reputation: 85

Angular 2 http.get() with dynamic options parameter

In an angular app that uses HttpClient service, The code below works fine:

this.http.get(myUrl, {responseType: 'json'})

I need to send the responseType as a dynamic parameter, something like:

this.http.get(myUrl, { responseType: (condition ? 'json' : 'blob') })

or like:

 let options = { responseType: 'json' };
 if (condition)
      options = { responseType: 'blob' };
 this.http.get(myUrl, options)

but typescript does not like it, and shows an error: No overload matches this call

What am I doing wrong and how can I achieve this?

Thanks!

Note: This Type "json" | undefined not satisfied by "json" in Angular HttpClient

does not meet my requirement, but helps me to correct the code:

const options: { responseType: "json" } = { responseType: "json" };
const optionsBlob: { responseType: "blob" } = { responseType: "blob" };

this.http.get(myUrl, condition ? options : optionsBlob)

yet, compiler is not satisfied, and shows the previous error.

Upvotes: 1

Views: 1077

Answers (1)

Chris Hamilton
Chris Hamilton

Reputation: 10954

HttpClient.get() has overloads based on the response type: https://angular.io/api/common/http/HttpClient. You can see that providing a different response type calls a different function. So this.http.get(myUrl, options); is ambiguous, the compiler does not know which function you are referring to. Instead, just call the correct overload as part of your condition.

    if (condition) this.http.get(myUrl, { responseType: 'blob' });
    else this.http.get(myUrl, { responseType: 'json' });

Alternative with HttpClient.request() instead.

    const responseType = condition ? 'json' : 'blob';
    const request = new HttpRequest('GET', myUrl, { responseType });
    this.http.request(request);

Upvotes: 1

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