merge the value of two objects increasing the value of a key if matched [Javascript]

Question

Given two object:

const obj1 = {
  1: 5,
  2: 4
};

const obj2 = {
  1: 10,
  2: 1,
  3: 1
};

How do I merge them with Lodash Merge to create the resulting object of:

const newObj = {
  1: 15,
  2: 5,
  3: 1
};

What have you tried? Nothing because I have no idea how to use merge in this way or if merge is the right way.

Answer 1

Use _.mergeWith() - it has a customizer that enables you to define the how will properties be merged.

 const obj1 = { 1: 5, 2: 4 }; const obj2 = { 1: 10, 2: 1, 3: 1 }; const result = _.mergeWith({}, obj1, obj2, (o1, o2) => { if(_.isNumber(o1)) { return o1 + o2; } }); console.log(result); 

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