Angular 2 how to make child component wait for async data to be ready

Question

I\'m passing async data from a parent component to a child component. And the child component needs to know the length of the data in order to do something.

How the

Answer 1

Simpler solution:

ngOnChanges(changes: SimpleChanges) {
    if (changes['items'].currentValue) {
        this.items = items
    }
}