Array.remove prototype function

README.md

This is a small snippet that gives Javascript arrays the (much-needed) ability to remove elements based on value. Example:

items = [1,2,3,3,4,4,5];
items.remove(3); // => [1,2,4,4,5]

array_in_place.js

Array.prototype.remove = function(elem) {
    var ai = this.indexOf(elem);
    while(ai > -1){
        this.splice(ai,1);
        ai = this.indexOf(elem);
    }
    return this;
};

array_new.js

Array.prototype.indices = function(elem) {
    var indices = [];
    var index = this.indexOf(elem);

    while (true) {
        if (index < 0) {
            break;
        }
        else {
            indices.push(index);
        }
        index = this.indexOf(elem, index+1);
    }
    return indices;
}

Array.prototype.remove = function(elem) {
    var indices = this.indices(elem);

    if (indices.length == 0) {
        return this;
    }
    else {
        var pos = indices[0];
        var previous_pos;
        var result = this.slice(0, pos);
        var rest;

        for (var i=1; i<indices.length; i++) {
            pos = indices[i];
            previous_pos = indices[i-1]
            rest = this.slice(previous_pos+1, pos);
            result.push.apply(result, rest);
        }

        rest = this.slice(pos+1)
        result.push.apply(result, rest);
        return result;
    }
};

You can merge it manually by checking out your gist via git and merging my fork, [email protected]:1787122.git

Merged!

One thing to note, is that this modifies the original array, whereas the original solution returns a new array.

Original:

var items = [1,2,3,3,4,4,5];
items.remove(3); // => [1,2,4,4,5]
items; // => [1,2,3,3,4,4,5];

New:

var items = [1,2,3,3,4,4,5];
items.remove(3); // => [1,2,4,4,5]
items; // => [1,2,4,4,5]

To get this working like it was before, you would have to copy the array first, via slice or concat:

items.slice(0).remove(3);

I'll add the first one back as well, with that note. Thanks for reminding...I noticed it and forgot to mention it.

Of course, you could always do something like:

Array.prototype.remove = function(elem, doCopy) {
    var a = doCopy ? this.slice(0) : this;
    var ai = a.indexOf(elem);
    while(ai > -1){
        a.splice(ai,1);
        ai = a.indexOf(elem);
    }
    return a;
};

Which would give you the best of both worlds.

doCopy = false (or undefined):

var items = [1,2,3,3,4,4,5];
items.remove(3); // => [1,2,4,4,5]
items; // => [1,2,4,4,5]

doCopy = true:

var items = [1,2,3,3,4,4,5];
items.remove(3, true); // => [1,2,4,4,5]
items; // => [1,2,3,3,4,4,5];