CODEWITHSUNDEEP
javascriptlodash
Keselme
Keselme

Reputation: 4249

How to get the difference between two objects?

If I have two objects:

const objA = { name: 'Tom', age: '20', location: 'London' };
const objB = { name: 'Jimmy', age: '35', occupation: 'Welder', hobbies: ['Football'] }

How can I get only the values that are only present in objA and not in objB, I want the result to be:

{
    location: 'London'
}

Is there a method in Lodash for that?

Upvotes: 0

Views: 2602

Answers (3)

connexo
connexo

Reputation: 56754

Native, modern JS only:

const objA = { name: 'Tom', age: '20', location: 'London' };
const objB = { name: 'Jimmy', age: '35', occupation: 'Welder', hobbies: ['Football'] };

const diff = Object.fromEntries(Object.entries(objA).filter(([k, v]) => !Object.hasOwn(objB, k)));

console.log(diff);

Please note that this solution makes use of several relatively new additions to JavaScript:

Upvotes: 4

Terry Lennox
Terry Lennox

Reputation: 30685

You can use _.pickBy() and _.has() to get the desired result using lodash.

We'll use the predicate: (value, key) => !_.has(objB, key) to return entries only present in objA.

const objA = { name: 'Tom', age: '20', location: 'London' };
const objB = { name: 'Jimmy', age: '35', occupation: 'Welder', hobbies: ['Football'] }

const difference = _.pickBy(objA, (value, key) => !_.has(objB, key));
console.log('Difference:', difference)
   
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js" integrity="sha512-WFN04846sdKMIP5LKNphMaWzU7YpMyCU245etK3g/2ARYbPK9Ub18eG+ljU96qKRCWh+quCY7yefSmlkQw1ANQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

You can also do this in vanilla JavaScript using Object.entries(), Object.fromEntries() and Array.filter():

const objA = { name: 'Tom', age: '20', location: 'London' };
const objB = { name: 'Jimmy', age: '35', occupation: 'Welder', hobbies: ['Football'] }

const difference = Object.fromEntries(
    Object.entries(objA).filter(([key, value]) => {
        return !objB.hasOwnProperty(key);
    })
);

console.log('Difference:', difference)

Upvotes: 2

Crist&#243;v&#227;o F&#225;bio
Crist&#243;v&#227;o F&#225;bio

Reputation: 141

Have you ever tried something like this?

for (key in objA) {
  if (!objB[key]) {
    console.log(key, objA[key]);
  }
}

or something like:

let newObj = {};

for (key in objA) {
  if (!objB[key]) {
    newObj[key] = objA[key];
  }
}

console.log(newObj);

Upvotes: 0

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