use argument as object property in angular

Question

Is there any way to convert string as object property in angular? eg:

getErrorMessage(error_type) {
    return this.userForm.controls.{error_type}.hasError('required') ? 'You must enter a value' : '';
}

getErrorMesssage('email');

The function should work something like

return this.userForm.controls.email.hasError('required') ? 'You must enter a value' : '';

Answer 1

You can use get() function:

getErrorMessage(controlName: string) {
    return this.userForm.get(controlName).hasError('required') ? 'You must enter a value' : '';
}

The only thing is that you want to pass the control name, not the error type, what I can see from your variable naming.

Answer 2

getErrorMessage(error_type) {
  return this.userForm.controls[error_type].hasError('required') ? 'You must enter a value' : '';
}

Square brackets, not curly.

Answer 3

In a general way, you can access object properties using bracket notation:

const thing = { email: 'foo@bar.com };
console.log(thing['email']); // prints 'foo@bar.com'