Disable the entire form at once (Angular reactive form)

this.tempForm.disable();

Disables the control. This means the control will be exempt from
validation checks and excluded from the aggregate value of any parent.
Its status is DISABLED.

If the control has children, all children will be disabled to maintain
the model.

LINK

UPDATE

Plunker link – https://plnkr.co/edit/CFC4uKpvfE4otJ2PWdkc?p=preview