How to check if array contains objects

Question

I have array, created from json:

var array = [{"name":"name1","group":"group1","id":"123", ...},
{"name":"name2","group":"group2","id":"456", ...},
{"name":"name3","group":"group1","id":"789", ...}];

After I get another array:

var array1 = [{"name":"name1","group":"group1","id":"123", ...},
{"name":"name4","group":"group1","id":"987", ...}]

I need to push items from second array into first, but how can I check if first array contains objects from second array?

Each object in array contain more property and some of them are created dynamically so I can't check for example by indexOf(). All solutions that I found works only with simple objects like Int. It will be great if I could check by property "id" for example.

Possible duplicate of [How do I check if an array includes an object in JavaScript?](https://stackoverflow.com/questions/237104/how-do-i-check-if-an-array-includes-an-object-in-javascript) — Yogesh, Mar 06 '18 at 15:07

score 2 · Accepted Answer · answered Mar 06 '18 at 15:09

2

Use find first

var newObj = {"name":"name2","group":"group2","id":"456"};
var value = array.find( s => s.id == newObj.id );

Now push if the value is not found

if ( !value )
{
   array.push( newObj ) 
}

answered Mar 06 '18 at 15:09

gurvinder372

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Or use `array.some`. – str Mar 06 '18 at 15:11
Yes, if only a boolean is required. However, find can be useful if existing value has to be updated. – gurvinder372 Mar 06 '18 at 15:12
@gurvinder372 That works, thank you. I expected that solution must be easy, but not expected that so easy :) – Ihor Mykytiv Mar 06 '18 at 15:21

score 0 · Answer 2 · answered Mar 06 '18 at 15:37

(More generic)you can do this one line using following (which will add all object which is not in array).

array.concat(array1.filter(x=>!array.find(s=>s.id==x.id)));

var array = [{"name":"name1","group":"group1","id":"123"},
             {"name":"name2","group":"group2","id":"456" },
             {"name":"name3","group":"group1","id":"789"}];

var array1 = [{"name":"name1","group":"group1","id":"123"},
              {"name":"name4","group":"group1","id":"987"}];

array=array.concat(array1.filter(x=>!array.find(s=>s.id==x.id)));
console.log(array);

How to check if array contains objects

2 Answers2