The subscribe function failed to activate

Question

The subscribe function failed to activate

My Angular application includes a form and a submit button. The issue arises when I fill out the form and submit it; if the database injection operation is successful, I want to display a success message and clear the form automatically. I attempted to achieve this by utilizing the subscribe method, but for some reason, the code never enters this method and the desired functionalities do not get triggered.

insertRecord(form : NgForm){
    this.service.postAsset(form.value).subscribe(res =>{
    this.toastr.success('Inserted successfully', 'Asset Register');
    this.resetForm(form);
    });
  }

The postAsset method works correctly, adding the value to the database table. However, the subscribe method does not seem to be functioning as expected. What could be causing this problem? Any assistance would be greatly appreciated.

Edit: Upon request, here is the implementation of the postAsset() method;

postAsset(formData: Asset){
    return this.http.post(this.rootURL + '/Create', formData);
  }

Edit 2: The error occurs a few seconds after submitting the form;

SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>)
    at XMLHttpRequest.onLoad (http://localhost:4200/vendor.js:13804:51)
    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (http://localhost:4200/polyfills.js:2781:31)
    at Object.onInvokeTask (http://localhost:4200/vendor.js:59285:33)
    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (http://localhost:4200/polyfills.js:2780:60)
    at Zone.push../node_modules/zone.js/dist/zone.js.Zone.runTask (http://localhost:4200/polyfills.js:2553:47)
    at ZoneTask.push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask [as invoke] (http://localhost:4200/polyfills.js:2856:34)
    at invokeTask (http://localhost:4200/polyfills.js:4102:14)
    at XMLHttpRequest.globalZoneAwareCallback (http://localhost:4200/polyfills.js:4139:21)

angular typescript

Answer 1

Answer №1

Consider adding the option of {responseType: 'text'} to your POST request using HttpClient:

postAsset(formData: Asset) {
  return this.http.post(this.rootURL + '/Create', formData, { responseType: 'text' });
}

The documentation for HttpClient mentions this under Requesting non-JSON data.

It appears that the server is returning something other than application/json. By default, HttpClient tries to parse JSON data unless a different type is specified. Trying to parse non-JSON data would lead to the error you are encountering.

If possible, it is advisable to always return application/json from the server to avoid such issues.

I hope this explanation helps!

Answer 2

Consider adding the option of {responseType: 'text'} to your POST request using HttpClient:

postAsset(formData: Asset) {
  return this.http.post(this.rootURL + '/Create', formData, { responseType: 'text' });
}

The documentation for HttpClient mentions this under Requesting non-JSON data.

It appears that the server is returning something other than application/json. By default, HttpClient tries to parse JSON data unless a different type is specified. Trying to parse non-JSON data would lead to the error you are encountering.

If possible, it is advisable to always return application/json from the server to avoid such issues.

I hope this explanation helps!

Answer 3

Answer №2

Make a small adjustment to your code by following these steps:

uploadAsset(formData: Asset){
    return this.http.post(this.rootURL + '/Create', formData)
        .pipe(
            map((response: any) => {
                return response;
            })
        );
  }

Don't forget to include the following line at the beginning of your file:

import { map } from 'rxjs/operators';

Answer 4

Make a small adjustment to your code by following these steps:

uploadAsset(formData: Asset){
    return this.http.post(this.rootURL + '/Create', formData)
        .pipe(
            map((response: any) => {
                return response;
            })
        );
  }

Don't forget to include the following line at the beginning of your file:

import { map } from 'rxjs/operators';

The subscribe function failed to activate

Answer №1

Answer №2

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