What is the in-place alternative to Array.prototype.filter()

Question

I\'ve got an array that I would like to remove some elements from. I can\'t use Array.prototype.filter(), because I want to modify the array in place (because i

Answer 1

The currently selected answer works perfectly fine. However, I wanted this function to be a part of the Array prototype.

Array.prototype.filterInPlace = function(condition, thisArg) {
    let j = 0;

    this.forEach((el, index) => {
        if (condition.call(thisArg, el, index, this)) {
            if (index !== j) {
                this[j] = el;
            }
            j++;
        }
    })

    this.length = j;
    return this;
}

With this I can just call the function like so:

const arr = [1, 2, 3, 4];
arr.filterInPlace(x => x > 2);
// [1, 2]

I just keep this in a file called Array.js and require it when needed.