JavaScript: Array.prototype.filter

arrayX.filter(f)

Return a new array, with elements that f return true.

The function f is passed 3 args:

1. current_element
2. current_index
3. arrayX.

const f_isEven = ((x) => (x % 2 === 0));

const xx = [7, 3, 4, 2];

console.log(xx.filter(f_isEven)); // [ 4, 2 ]

// original not changed
console.log(xx); // [ 7, 3, 4, 2 ]

arrayX.filter(f, thisArg)

Use thisArg for this Binding of f. If it is not given, undefined is used.