Question

What does the keyword slice do? What are some practical uses of slice?

Answer 1

Slice in javascript returns a copy of part of an array.

Step-by-step explanation:

The prototype is slice(start, end), and the returned array contains copies of the elements of the original array, starting at index 'start', up to but excluding index 'end'.

Here is an example from the mozilla documentation:

const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];

const citrus = fruits.slice(1, 3);

// fruits contains ['Banana', 'Orange', 'Lemon', 'Apple', 'Mango']

// citrus contains ['Orange','Lemon']

You could use slice to limit the number of elements of a large array, or to implement pagination. Note that the copied array is a shallow copy, which means that if the elements are objects themselves, both the original and the copied array reference the same objects.