Do you know about mutable and immutable array methods? For example, what is the difference between splice and filter?

Mutable array methods modify the original array, while immutable ones return a new array without changing the original.

For example:

• splice — a mutable method. It modifies the original array by removing or adding elements.

const arr = [1, 2, 3, 4];
arr.splice(1, 2); // removes 2 elements starting from index 1
console.log(arr); // [1, 4]

• filter — an immutable method. It returns a new array with elements that pass the test, without changing the original.

const arr = [1, 2, 3, 4];
const filtered = arr.filter(x => x > 2);
console.log(filtered); // [3, 4]
console.log(arr); // [1, 2, 3, 4]

The choice between them depends on the task: if you need to preserve the original data, it is better to use immutable methods.