Combining all objects in an array into one

Question

I have an array of objects arr and I want to combine all of the objects in the array into one. There also are repetitive keys in the objects. Is there a way I can do this? Any help would be great.

var arr = [{ a: 1, a: 2 },
{ c: 1, d: 2 },
{ e: 14, f: 20 }];

The output I want is:

var arr = [{ a: 1, 
             a1: 2, 
             c: 1, 
             d: 2, 
             e: 14, 
             f: 20 }];

Do you mean that your output is supposed to have a, and b, and not a, and a, right? — KevBot
– KevBot, Commented Jul 7, 2016 at 15:26
I have multiple keys that are the same and want to rename them if there are duplicates. — Jacob Brauchler
– Jacob Brauchler, Commented Jul 7, 2016 at 15:28

tymeJV · Accepted Answer · 2016-07-07 15:16:56Z

2

Assuming all the keys are unique and you don't want to check, use reduce

var combinedKeys = arr.reduce(function(a, item) {
    Object.keys(item).map(function(key) {
        a[key] = item[key];
    });

    return a;
}, {});

var singleArrayOfCombinedKeys = [combinedKeys]; //[Object  a: 1b: 2c: 1d: 2e: 14f: 20__proto__: Object]

answered Jul 7, 2016 at 15:16

tymeJV

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7 Comments

Jacob Brauchler Over a year ago

This is a great answer, So how would I approach this issue if I do have keys that are not unique but still want them included.

tymeJV Over a year ago

@JacobBrauchler -- Depends on the outcome you want - are you looking to sum the numbers up?

Jacob Brauchler Over a year ago

no I I do not want to sum them up I want the object to look like the output in my question, I was just using the numbers as an example.

tymeJV Over a year ago

@JacobBrauchler -- Well if you have the same key twice, it can't be in the structure you want. Keys have to be unique. You can combine the values, or create an array of values.

Jacob Brauchler Over a year ago

is there a way that if it isn't unique you just rename it?

|

Mohit Bhardwaj · Accepted Answer · 2016-07-07 15:17:18Z

2

You can simply iterate through the array using for loop and assign all properties of each item to the combined object:

var arr = [{ a: 1, b: 2 },
{ c: 1, d: 2 },
{ e: 14, f: 20 }];

var combinedObj = {};

for( var i = 0; i < arr.length; i++ )
{
  var item = arr[i];
  for(var key in item )
  {
    combinedObj[key] = item[key];
  }//for()
}//for

console.log( combinedObj );

answered Jul 7, 2016 at 15:17

Mohit Bhardwaj

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Comments

Nenad Vracar · Accepted Answer · 2016-07-07 15:57:06Z

2

You could use reduce() and Object.assign()

var arr = [{ a: 1, b: 2 }, { c: 1, d: 2 }, { e: 14, f: 20 }];

var result  = [arr.reduce((r, o) => Object.assign(r, o), {})];
console.log(result)

edited Jul 7, 2016 at 15:57

answered Jul 7, 2016 at 15:19

Nenad Vracar

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