Access method's local variable in Angular unit test with Jasmine

Question

How can I access the type variable inside validate function? The problem is code-covarage shows that type in if statement not covered and I dunno how can I cover that.

interface NotUnique {
    notUnique: boolean;
}

@Injectable()

export class CheckExists implements AsyncValidator {
    constructor(
      private http: HttpClient
    ) {}

    async validate(control: FormControl): Promise<NotUnique> {
        try {
            if (!control || !control.parent) {
                return;
            }
            const value: string = control.value;
            const type = value.includes('@') ? 'email' : 'username';
            if (type) {
              const res = await this.http.post('/users/exists', {field: type, value: value}).toPromise();
              if (!(res as ExistsResponse).exists) {
                  return null;
              }
              return { notUnique: true };
            }
        } catch (err) {
            return null;
        }
    }
}

upd: image

Answer 1

If code-coverage is not covering if(type) that means your test is always returning from:

if (!control || !control.parent) {
   return;
}

In your unit test, you should fill the test data in such a way that it reaches till if (type) statement. That will happen if you make sure that control variable have proper data in it and has data in control.value too.