How to square all values of an object in JavaScript?

Question

Here is an object:

var a = { a: 1, b: 2, c: 3};

I would need to square all values from this object and the keys to remain the same, so new object to look like this:

var a1 = {a: 1, b: 4, c: 9}

My code - I extracted the keys and the values and created two separate arrays:

var a = {a:1, b: 2, c:3};
let key = Object.keys(a);
let value = Object.values(a);
v = [];
for (var i=0; i<value.length;i++){
  value[i]**2;
  v.push(value[i]**2);
}
console.log(v);

So here I got the array with squared values of all elements, but I don't know how to return it back to the object and get

{a: 1, b: 4, c: 9}

Um, that is two options.... Yes does not pick one or the other — epascarello, Feb 16 '21 at 14:17
Does this answer your question? [How do I loop through or enumerate a JavaScript object?](https://stackoverflow.com/questions/684672/how-do-i-loop-through-or-enumerate-a-javascript-object) — Heretic Monkey, Feb 16 '21 at 14:18
Loop thorugh the object and update the keys: `for(const k in a) a[k] = a[k] ** 2` — adiga, Feb 16 '21 at 14:22
See also [map function for objects (instead of arrays)](https://stackoverflow.com/q/14810506/215552) — Heretic Monkey, Feb 16 '21 at 14:24

Nina Scholz · Accepted Answer · 2021-02-16T14:22:20.910

To keep key and value together, you could work with the entries of the object and map new pairs and build an object from the new entries.

Methods:

Object.entries, get an array of all key/value pairs.
Object.fromEntries, create a new object from an array with key/value pairs.
Array#map, create a new array with the same length and different values.

const
    object = { a: 1, b: 2, c: 3 },
    result = Object.fromEntries(Object
        .entries(object)
        .map(([key, value]) => [key, value * value])
    );

console.log(result);

score 0 · Answer 2 · edited Feb 16 '21 at 14:23

0

You can also use Array.reduce on Object.entries. I.e.

const a = {
  a: 1,
  b: 2,
  c: 3
};

const result = Object.entries(a).reduce((acc, [key, value]) => {
  acc[key] = value ** 2;
  return acc
}, {})

edited Feb 16 '21 at 14:23

adiga

31,610
8
53
74

answered Feb 16 '21 at 14:20

Zoltan Magyar

864
1
6
18

[How do I create a runnable stack snippet?](https://meta.stackoverflow.com/questions/358992) – adiga Feb 16 '21 at 14:24

score 0 · Answer 3 · answered Feb 16 '21 at 14:37

0

var a = {
  a: 1,
  b: 2,
  c: 3
};

Object.keys(a).map(function(key, index) {
  a[key] = a[key] * a[key];
});

console.log(a)

answered Feb 16 '21 at 14:37

Tushar Wason

356
1
7

How to square all values of an object in JavaScript?

3 Answers3