Question

When does the ngOnInit() lifecycle hook in Angular initialize the component?

a) Before Angular first displays the data-bound properties
b) After Angular destroys the component
c) When the constructor is invoked
d) Only after all input properties have changed

Answer 1

The ngOnInit() lifecycle hook is called before Angular first displays the data-bound properties and after the constructor, serving as the initialization point for Angular components. The correct multiple-choice option is (A).

Step-by-step explanation:

The ngOnInit() lifecycle hook in Angular is a critical function in the initialization process of Angular components. The correct answer to when ngOnInit() is called is option (a): It initializes the component before Angular first displays the data-bound properties, but after the construction of the component's class. This is a point in the lifecycle where the input properties are set, and the component is ready to start data-bound input processing.

ngOnInit() is one of the lifecycle hooks provided by Angular, and it is called after the constructor of the component class has been executed. This lifecycle hook is a great place for initialization logic, such as fetching data or setting up subscriptions, that needs to occur once and does not depend on DOM rendering, which isn't available yet at this point. The correct multiple-choice option is (A).