Angular Web Framework Reactive Forms & Validation 2

Question 1

Which method on a FormGroup marks all descendant controls as touched?

Accepted Answer

markAllAsTouched()

Answer

`markAllAsTouched()` recursively marks every control in the group and its children as touched.

Question 2

What does the `updateOn` option set to `'blur'` do in a reactive form control?

Accepted Answer

Triggers validation only when the field loses focus

Answer

Setting `updateOn: 'blur'` defers value and validity updates until the user leaves the field.

Question 3

Which validator ensures a control's value matches a given regular expression?

Accepted Answer

Validators.pattern()

Answer

`Validators.pattern()` accepts a string or RegExp and validates the control value against it.

Question 4

How do you disable a specific FormControl inside a FormGroup without removing it?

Accepted Answer

Both A and C are valid approaches

Answer

You can call `control.disable()` at runtime or pass `{ disabled: true }` as the initial state object to `FormBuilder.control()`.

Question 5

What value does `formControl.value` return when the control is disabled?

Accepted Answer

The current value is still returned

Answer

A disabled control retains its value; `formControl.value` still returns the current value even when disabled.

Angular Web Framework Practice Test