How can I inform Typescript that a function will never return null in this specific scenario?

Need help with implementing typescript strictNullChecks in an Angular 5 project.

The form structure is as follows:

this.signinForm = this.fb.group({
  emailAddress: ['', NGValidators.isEmail()],
  password: ['', Validators.required],
  rememberMe: false,
});

To access the rememberMe control, I use

this.signinForm.get('rememberMe')
. However, since the return type of FormGroup#get method is AbstractControl | null, TypeScript throws an error for
this.signinForm.get('rememberMe').value
(as it might be null).

Is there a way to specify to TypeScript that, in this particular scenario, the return value of

this.signinForm.get('rememberMe')
will always be AbstractControl and not AbstractControl | null?

Answer №1

Employ the ! operator to access the value:

this.loginForm.get('rememberMe')!.value

Answer №2

To coerce the type in TypeScript, you can use the syntax as [type]. For example, in your current situation you could write

(this.loginForm.get('rememberMe') as FormControl).value
.

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