How to get all the keys for a matching value in javascript

Question

I want to fetch all the keys for a matching value in javascript.

{  
 'aaa': 2,
 'bbb': 7,
 'ccc': 7 
}

I want to fetch all the keys where the value is matching without running a loop.

For example: I am having value 7 and I want to get all the keys which are having value 7 i.e. 'bbb' and 'ccc'. Is there any way to do it?

Why are you trying to avoid a loop? (Telling us might make this questions clearer) — doctorlove, Jun 12 '19 at 11:43
Just wanted to go with some predefined function about which I am not aware of — Sweta Sharma, Jun 12 '19 at 11:44
What you're asking to do is fundamentally impossible without a loop *somewhere*. — CertainPerformance, Jun 12 '19 at 11:44
You can't do it without a recursive function or a loop. At least I am not aware of any other option. — Victor, Jun 12 '19 at 11:45
Possible thread duplicated. Check [this](https://stackoverflow.com/questions/9907419/how-to-get-a-key-in-a-javascript-object-by-its-value) — wasanga7, Jun 12 '19 at 11:48
Possible duplicate of [How to get a key in a JavaScript object by its value?](https://stackoverflow.com/questions/9907419/how-to-get-a-key-in-a-javascript-object-by-its-value) — wasanga7, Jun 12 '19 at 11:48
You should go ahead and try with a loop then, and come back if you get stuck with that code you've written. — Andy, Jun 12 '19 at 11:49

score 4 · Answer 1 · answered Jun 12 '19 at 11:51

4

You could get the keys and filter the by checking the value.

var object = { aaa: 2, bbb: 7, ccc: 7 },
    result = Object.keys(object).filter(k => object[k] === 7);

console.log(result);

answered Jun 12 '19 at 11:51

Nina Scholz

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score 1 · Answer 2 · answered Jun 12 '19 at 12:07

Something like swap the keys with the values like that ?

var data = {
 'aaa': 2,
 'bbb': 7,
 'ccc': 7 
};

var newData = Object.keys(data).reduce(function(obj,key){
   if (typeof obj[ data[key] ] === 'undefined') {
        obj[ data[key] ] = new Array(key);
   } else {
        obj[ data[key] ].push (key);
   }
   return obj;
},{});
console.log(newData);

Or just for retrieving the keys of matching values like this ?

const keys = Object.keys(data).filter(function(key) {return data[key] === 7});
console.log (keys);

How to get all the keys for a matching value in javascript

2 Answers2