Merge specific array of objects with new key

Question

I am trying to merge two object into one (obj1 and obj2 into objResult):

var obj1 = {
 0: [{obj1key1: 'obj1value1'}, {obj1key2: 'obj1value2'}],
 1: [{obj1key3: 'obj1value3'}, {obj1key4: 'obj1value4'}],
 2: [{obj1key5: 'obj1value5'}, {obj1key6: 'obj2value6'}]
};
var obj2 = {
 0: [{obj2key1: 'obj2value1'}, {obj2key2: 'obj2value2'}],
 1: [{obj2key3: 'obj2value3'}, {obj2key4: 'obj2value4'}],
 2: [{obj2key5: 'obj2value5'}, {obj2key6: 'obj2value6'}]};
var objResult = {
 0: {
   0: [{obj1key1: 'obj1value1'}, {obj1key2: 'obj1value2'}],
   1: [{obj2key1: 'obj2value1'}, {obj2key1: 'obj2value1'}]
 },
 1: {
   0: [{obj1key3: 'obj1value3'}, {obj1key4: 'obj1value4'}],
   1: [{obj2key3: 'obj2value3'}, {obj2key4: 'obj2value4'}]
 },
 2: {
   0: [{obj1key5: 'obj1value5'}, {obj1key6: 'obj1value6'}],
   1: [{obj2key5: 'obj2value5'}, {obj2key6: 'obj2value6'}]
 }
}

I tried jQuery's and lodash's merge functions but without success. Could you advise the best way to merge these two objects into one? Either with plain JS or jquery/lodash.

Please post what you've tried

Sterling Archer
– Sterling Archer

2015-12-10 17:39:35 +00:00
Commented Dec 10, 2015 at 17:39 — Sterling Archer
– Sterling Archer, Commented Dec 10, 2015 at 17:39

James Brierley · Accepted Answer · 2015-12-10 17:46:17Z

1

Iterate over the keys in one of the objects, and for each one, set that key on the result object to an object containing the values from both your original objects.

function merge(obj1, obj2) {
    var objResult = {};

    Object.keys(obj1).forEach(function(key) {
        objResult[key] = {
            0: obj1[key],
            1: obj2[key]
        }
    })

    return objResult;
}

This assumes that both objects have the same set of keys. If they don't, you can iterate over the keys of both objects, and this will set undefined as the value when that object does not contain that key.

Demo

answered Dec 10, 2015 at 17:46

James Brierley

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Comments

AhmadAssaf · Accepted Answer · 2015-12-10 17:46:31Z

Assuming that the two objects are of the same size (length)

var obj1 = {
 0: [{obj1key1: 'obj1value1'}, {obj1key2: 'obj1value2'}],
 1: [{obj1key3: 'obj1value3'}, {obj1key4: 'obj1value4'}],
 2: [{obj1key5: 'obj1value5'}, {obj1key6: 'obj2value6'}]
};
var obj2 = {
 0: [{obj2key1: 'obj2value1'}, {obj2key2: 'obj2value2'}],
 1: [{obj2key3: 'obj2value3'}, {obj2key4: 'obj2value4'}],
 2: [{obj2key5: 'obj2value5'}, {obj2key6: 'obj2value6'}]};

var result = {};
_.each(obj1, function(obj, key){
   result[key] = [];
   result[key].push(obj);
   result[key].push(obj2[key]);    
});

$('body').append('<pre><code>' + JSON.stringify(result) + '</code></pre>');

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://lodash.com/_js/lodash.js"></script>

Of course, if you have multiple lengths, you need to iterate on the bigger one and keep track of the size

Quentin Roy · Accepted Answer · 2015-12-10 17:55:14Z

1

Here is a plain JS example that can manage objects with different sizes.

var obj1 = {
 0: [{obj1key1: 'obj1value1'}, {obj1key2: 'obj1value2'}],
 1: [{obj1key3: 'obj1value3'}, {obj1key4: 'obj1value4'}],
 2: [{obj1key5: 'obj1value5'}, {obj1key6: 'obj2value6'}]
};
var obj2 = {
 0: [{obj2key1: 'obj2value1'}, {obj2key2: 'obj2value2'}],
 1: [{obj2key3: 'obj2value3'}, {obj2key4: 'obj2value4'}],
 2: [{obj2key5: 'obj2value5'}, {obj2key6: 'obj2value6'}]};

var obj3 = [obj1, obj2].reduce(function(result, obj, objNum){
  return Object.keys(obj).reduce(function(result, k){
    result[k] = result[k] || {};
    result[k][objNum] = obj[k];
    return result;
  }, result);
}, {});

console.log(obj3);

answered Dec 10, 2015 at 17:55

Quentin Roy

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