How to add the values from one object to another assuming the keys are identical

Question

I've got 2 arrayys and I want to add the values of each of the keys together

const baseStats =  { CHA: 2, CON: 1, DEX: 1, HP: 12, INT: 1, STR: 2, WIS: 1 };
const bonusStats = { CHA: 0, CON: 0, DEX: 0, HP: 2,  INT: 0, STR: 2, WIS: 1 };

Expected result = { CHA: 2, CON: 1, DEX: 1, HP: 14, INT: 1, STR: 4, WIS: 2 };

Loop through one of the object `for let key in obj...` and add their values to each other. This is one the simplest way to get what you want. — Daniyal Lukmanov, Feb 01 '20 at 13:02
Looks like [this is a similar question](https://stackoverflow.com/questions/43249813/how-to-sum-two-object-values-in-javascript/43249890) Bill :) — micnil, Feb 01 '20 at 13:05

score 1 · Answer 1 · answered Feb 01 '20 at 13:04

1

Can you try to do this?

var result = {};

for(var key in baseStats){
    result[key] = baseStats[key] + bonusStats[key];
}

console.log(result);

answered Feb 01 '20 at 13:04

webprogrammer

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You should use `const` instead of `var`. – Kamil Augustyniak Feb 01 '20 at 13:19

score 0 · Answer 2 · answered Feb 01 '20 at 13:12

0

An alternative to @webprogrammer 's answer, assume the two objects you have has distinct keys:

let result = {};

for (let [key, value] of Object.entries(baseStats)) {
   result[key] = bonusStats[key] + value
}

You can read this if you want to know more about entries.

answered Feb 01 '20 at 13:12

Andus

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You should use `const` instead of `let`. – Kamil Augustyniak Feb 01 '20 at 13:19
@KamilAugustyniak I agree that in most cases it's beneficial to define object as const. However, in terms of achieving the result that the OP wants, there's no difference. – Andus Feb 01 '20 at 14:09

Kamil Augustyniak · Answer 3 · 2020-02-01T13:24:16.407

0

Another alternative, I use Object.keys and forEach

const result = {};
Object.keys(baseStats).forEach(key => result[key] = baseStats[key] + bonusStats[key]);

I've edited it based on the comment.

edited Feb 01 '20 at 13:24

answered Feb 01 '20 at 13:18

Kamil Augustyniak

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You should use `.forEach` instead of `.map()` if all you're going to use it for is iteration and causing side-effects. `.map()` is used when you want to convert each element in the array to something else (ie: map each element to something else). So `.map()` returns the changed array. You're not using the returned value of `.map()` here, so `.forEach()` would be better here ;) – Nick Parsons Feb 01 '20 at 13:22
1

Yes, I agree. My mistake, I've edited the answer. – Kamil Augustyniak Feb 01 '20 at 13:24

How to add the values from one object to another assuming the keys are identical

3 Answers3