Ionic 3 Login Authentication Using API - Cannot read property 'json' of null

Question

I am doing authentication in Ionic 3 using API but In the login process, it is showing error: Cannot read property \'json\' of null

This is my provi

Answer 1

The problem is in your restapi.ts constructor, HttpClient causing the issue;

  constructor(public http: HttpClient) {
    console.log('Hello RestapiProvider Provider');
  }

Change that to this,

  constructor(public http: Http) {
    // console.log('Hello RestapiProvider Provider');
  }

You have an error on this part {headers: headers} here is your error :

Argument of type '{ headers: Headers; }' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'. Types of property 'headers' are incompatible. Type 'Headers' is not assignable to type 'HttpHeaders | { [header: string]: string | string[]; }'. Type 'Headers' is not assignable to type '{ [header: string]: string | string[]; }'. Index signature is missing in type 'Headers'.

Error is pretty clean so does not need any explanation, your code will work without any issue if you do that change. I tested on my local.