How to iterate over this javascript object?

Question

I have an object like below-

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};

I get individual values like

console.log(objResult[0].name); // xyz
console.log(objResult[1].name); // pqr

So when I iterate, I thought using for loop will do but objResult.length is giving value undefined

for(var i =0;i< objResult.length; i++){
console.log(objResult[i]);
}

Can u please help how to do it

An object doesn't have automatically a `length` property like arrays do. Also, object properties are unordered and doesn't guarantee that all browsers will get them in same order. — Kaddath, Jun 25 '19 at 11:40
@Kaddath Property ordering is guaranteed to a certain degree in modern browsers in ES 2015 https://www.stefanjudis.com/today-i-learned/property-order-is-predictable-in-javascript-objects-since-es2015/ — connexo, Jun 25 '19 at 11:43
@connexo agreed totally, but you can't ensure people will use a modern browser (well, unless you specifically do) — Kaddath, Jun 25 '19 at 11:43

score 4 · Accepted Answer · answered Jun 25 '19 at 11:40

Use for in syntax for iteration object properties.

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};
for(const item in objResult)
  console.log(objResult[item])

You can read about this https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in

score 3 · Answer 2 · answered Jun 25 '19 at 11:43

Don't use an object, use an array instead:

var arrResult = [{name:"xyz"}, {name:"pqr"}, {name:"abc"}];

This will have a .length property and can be iterated normally with for … of loops.

If you actually got an object back, best convert it to an array:

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};
var arrResult = Object.assign([], objResult);

score 1 · Answer 3 · answered Jun 25 '19 at 11:40

1

The ‘for...in’ construct allows you to iterate over all keys present on an object, even unowned.

The syntax is such: ‘for (const key in this) { }’

answered Jun 25 '19 at 11:40

Isaaс Weisberg

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claasic · Answer 4 · 2019-06-25T11:52:41.273

You can use Object.values or Object.entries and even Object.keys depending on what you need of the Object itself and then iterate over those results (as they are now an array) with either forEach or map.

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};

Object.values(objResult).forEach(({name}) => console.log(name));

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};

Object.entries(objResult).forEach(([k,{name}]) => console.log(name))

To access how many keys your object includes run the following:

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};
    lgth      = Object.keys(objResult).length;

console.log(lgth);

Why I did not use map but forEach instead in this case: map exists to create copies of existing values and map / transform them which is not what I want for a console.log.

score 1 · Answer 5 · answered Jun 25 '19 at 13:17

1

Another way to do this is by using Object.keys() method.

It returns the list of keys in the object and then you can iterate over that list to get hold of the values.

for(let key in Object.keys(objResult)) {
    console.log(objResult[key]);
}

answered Jun 25 '19 at 13:17

Akash Tomar

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score 0 · Answer 6 · answered Jun 25 '19 at 11:44

When using ES5 or later, you can map the object values within a single line of code like this:

Object.values(objResult).map(i => console.log(i));

Here you first create an array of the values with Object.values(objResult) and then iterate over every element using the map function.

If you do not want to use the map function you can iterate over the array with an loop (for example "for of" or "for in")

score 0 · Answer 7 · answered Jun 25 '19 at 11:51

As specified by you, we can do that using for, but with some modifications.

var objResult = {0:{name:"xyz"}, 1:{name:"pqr"}, 2:{name:"abc"}};
for(let key in objResult) {
    let value = objResult[key].name;
    console.log(value);
}

Hope, this helps you

How to iterate over this javascript object?

7 Answers7