Javascript call method is not working on an Array forEach

Question

var obj = {
    0: 'Asad',
    1: 'Ali',
    2: 'Rizwan'
}
console.log(obj);
let FOREAC = Array.prototype.forEach;

FOREAC.apply(obj , ((item) => {

    console.log('ITEM LOGS');

    console.log(item);

    return true;
}))

Above is the code I am using to iterate my object obj. It does not show any output. Thanks In Advance

I am trying to iterate my object obj. But my code does not shows any output

`obj` doesn't have a `length` property... – VLAZ Apr 14 '23 at 07:24 — VLAZ, Apr 14 '23 at 07:24
Any way to add length property to my `obj` – asad nextstair Apr 14 '23 at 07:26 — asad nextstair, Apr 14 '23 at 07:26

score 1 · Answer 1 · answered Apr 14 '23 at 07:33

1

You could convert the object with index like keys to an array and use it.

const
    object = { 0: 'Jo', 1: 'Ali', 2: 'Jane' },
    array = Object.assign([], object);
    
array.forEach(v => console.log(v));

answered Apr 14 '23 at 07:33

Nina Scholz

376,160
25
347
392

score 1 · Accepted Answer · answered Apr 14 '23 at 07:45

1

How about a simple for..in loop. This literally what it's made for.

var obj = {
  0: 'Asad',
  1: 'Ali',
  2: 'Rizwan'
}
console.log(obj);

for (const key in obj) {
  console.log('item', key, obj[key]);
}

answered Apr 14 '23 at 07:45

Thomas

11,958
1
14
23

score 1 · Answer 3 · answered Apr 14 '23 at 08:52

Array methods like Array#forEach() are intentionally generic to work with not only arrays but any array-like object. In short, an array-like has indexes as keys¹ and a length property².

The following object has indexes but not a length property:

var obj = {
  0: 'Asad',
  1: 'Ali',
  2: 'Rizwan'
}

Once length is added Array#forEach can be used against it using Function#call():

var obj = {
    0: 'Asad',
    1: 'Ali',
    2: 'Rizwan',
    length: 3
}

let FOREAC = Array.prototype.forEach;

FOREAC.call(obj, (item) => {
    console.log('ITEM LOGS');
    console.log(item);

    return true;
});

.as-console-wrapper { max-height: 100% !important; }

Or Function#apply():

var obj = {
    0: 'Asad',
    1: 'Ali',
    2: 'Rizwan',
    length: 3
}

let FOREAC = Array.prototype.forEach;

FOREAC.apply(obj, [(item) => {
    console.log('ITEM LOGS');
    console.log(item);

    return true;
}]);

.as-console-wrapper { max-height: 100% !important; }

¹ non-negative integers
² also a non-negative integer. It should show the next available index.

score 0 · Answer 4 · answered Apr 14 '23 at 07:27

You can use Object.entries to iterate over all pairs in an object.

var obj = {
   0: 'Asad',
   1: 'Ali',
   2: 'Rizwan'
}

for (const [key, value] of Object.entries(obj)) {
   console.log(`${key}: ${value}`);
}

Edit: However as your object does not contain any information in the key position (only indexes) you could also use Object.values to generate an Array from the object values:

var obj = {
   0: 'Asad',
   1: 'Ali',
   2: 'Rizwan'
}

console.log(Object.values(obj)

Javascript call method is not working on an Array forEach

4 Answers4