deleting array items in javascript with forEach() and splice()

gistfile1.js

// This is from my comment here: http://wolfram.kriesing.de/blog/index.php/2008/javascript-remove-element-from-array/comment-page-2#comment-466561

/*
 * How to delete items from an Array in JavaScript, an exhaustive guide
 */

// DON'T use the delete operator, it leaves a hole in the array:
var arr = [4, 5, 6];
delete arr[1]; // arr now: [4, undefined, 6]

// DO use splice:
var arr = [4, 5, 6];
arr.splice(1, 1);

// If you want to find the item to delete you can use .indexOf()
var arr = [4, 5, 6];
var idx = arr.indexOf(5); // 1
// be careful, .indexOf() will return -1 if the item is not found
if (idx !== -1) {
    arr.splice(idx, 1);
}

// Not all browsers support .indexOf(), so here's a monkey-patch:
if (!Array.prototype.indexOf) {
    // augment the Array prototype with an indexOf that conforms
    // to ECMAScript5
    //   item - this is the object we're looking for
    //   start - this is where to start looking
    // returns the index of the item if found, otherwise -1
    Array.prototype.indexOf = function (item, start) {
        start = start || 0;
        for( ; start < this.length; start++) {
            if (this[start] === item) {
                return start;
            }
        }
        return -1;
    };
}



// If you want to splice in an iterator like Array's forEach()
// DON'T do this:
var arr = [5, 6, 7, 8, 9];
arr.forEach(function (item, index) {
    if (item === 7 || item === 8) {
        arr.splice(index, 1);
    }
});
// arr is now something like: [5, 6, 8, 9]


// DO use the third argument to the iterator function:
var arr = [5, 6, 7, 8, 9];
arr.forEach(function (item, index, arr) {
    if (item === 7 || item === 8) {
        arr.splice(index, 1);
    }
});
// arr is now [5, 6, 9]
/*
 * The 'arr' in the iterator is a clone of the original arr,
 * and at the end of the forEach, the original gets its length
 * and all elements set to the clone's length and elements.
*/


// Of course not all browsers Array implement forEach so here's a monkey-patch:
if (!Array.prototype.forEach) {
    // augment the Array prototype with a forEach that conforms
    // to ECMAScript5
    //   iterator - a function with signature (item, index, array)
    //   context - an optional context to call the iterator, 'this'
    //             will be set to it inside of the iterator
    Array.prototype.forEach = function (iterator, context) {
        var arr = (new Array()).concat(this);  // clone this
        var i;
        for(i = 0; i < this.length; i++) {  // iterate over this, but use the clone
            iterator.call(context, arr[i], i, arr);
        }
        this.length = arr.length; // reset this to the clone's items
        for(i = 0; i < this.length; i++) {
            this[i] = arr[i];
        }
    };
}

nice !

nice!

Good!

Cool

thanks!

thx!

thanks!

use Array.filter

thanks! 👍

That reverse for loop is what i'm looking for! , Thanks!

very good, reverse for loop! , Thanks!

Very nice, thanks! By the way, there's an unfortunate "space" between the / and the * on Line 73... the space needs to go away in order for this to work.

Like...

/*
 * Comment...
 */

or

/**
 * Comment...
 */

Awesome. Thank you so much.

Biblical!

Nice Thanks :)

Nice！ Thanks！

need continue after splice in reverse for-loop

My case:

cash_menu.map((i, i_index) => {
    cash_menu[i_index].items = cash_menu[i_index].items.filter(item => {
            console.log(item)
            return item.Price !== 0
        }
    )
})

Very nice, thanks! By the way, there's an unfortunate "space" between the / and the * on Line 73... the space needs to go away in order for this to work.

Nothing like fixing something three years later, right?

need continue after splice in reverse for-loop

only if you are doing other things in the loop that you don't want to happen if you remove the item

thank you !

Thank you!