Find object's value

Question

Is there any not loop-based approach in JavaScript or JQuery that can check presence of some VALUE from object's properties. I mean here if I have

obj = { prop1:val, prop2:val2 }

is that possible with maybe one statement check is val2 presence among values of obj ?

UPDATE 1: The loop here is not the key! I can use loop if it is wrapped in some JQuery predefined function!

UPDATE 2: Writing a hand-made function is not so elegant, I think. I would like to find some library based solution for such a common and usual problem.

Short answer: no, you have to iterate over the object, or use a function that iterates over the object. — zzzzBov
– zzzzBov, Commented Nov 30, 2012 at 18:06
Depends what you are trying to do. Are you trying to test for the presence of a known property of an object in another? — Mike Bonds
– Mike Bonds, Commented Nov 30, 2012 at 18:10
@MichaelZ, you said "non loop-based approach" which is not possible as any function you might use to search would need to use a loop in one way or another. There are certainly elegant functions that exist so that you might call something along the lines of contains(obj, val2), but in that case the contains function would be loop-based. — zzzzBov
– zzzzBov, Commented Nov 30, 2012 at 18:19
It should be noted that the "duplicate" referenced isn't a duplicate at all -- that one is asking to search the text in all keys, not match them. — McGarnagle
– McGarnagle, Commented Nov 30, 2012 at 22:15

Selvakumar Arumugam · Accepted Answer · 2012-11-30 18:33:42Z

4

No you cannot find if a value exist in an object in one statement without looping.

You can use native API or a library.. but they are going to internally loop thru all values.

The toll on any other method will be same as iterating the object.. So I would write a simple for loop to do it.

I would simply write this 4 line code in my script file and include that script file instead of including a library.. which would be the same. http://jsfiddle.net/sQW4P/2/ <-- Incase if you need such a function.

edited Nov 30, 2012 at 18:33

answered Nov 30, 2012 at 18:08

Selvakumar Arumugam

79.9k15 gold badges123 silver badges139 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Michael Z Over a year ago

The loop here is not the key! I can use loop if it is wrapped in some JQuery predefined function!

zzzzBov Over a year ago

@MichaelZ, then you need to clarify your question.

Selvakumar Arumugam Over a year ago

@MichaelZ I don't think there is any such function in jQuery. So if you worried about having the loop inside your webpage.. move it to script file, name it a function and call the function. I think it should be available in some other library.. but adding a new library for this is no good.

Michael Z Over a year ago

Writing a hand-made function is not so elegant, I think. I would like to find some library based solution for such a common and usual problem.

Selvakumar Arumugam Over a year ago

@MichaelZ In my opinion, writing hand-made 1000 line code is not so elegant.. but looking for a library to write a 4 line code is not my style. jsfiddle.net/sQW4P/2

Faiz · Accepted Answer · 2012-11-30 18:24:58Z

1

This works with jQuery:

$.grep($.map(obj, function(v,k){return v}), function(el){return el == val2})

You could wrap it like so:

function hasVal(o, v) {
  $.grep($.map(o, function(v,k){return v}), function(el){return el == v}).length > 0
}

edited Nov 30, 2012 at 18:24

answered Nov 30, 2012 at 18:18

Faiz

16.3k5 gold badges50 silver badges39 bronze badges

Comments

McGarnagle · Accepted Answer · 2012-11-30 18:45:33Z

1

If you're ok using an external library, Underscore.js is fairly concise:

_.contains(_.values(obj), "val2");
// true

This is Underscore's values method:

Return all of the values of the object's properties.

Here is its implementation from the source code:

// Retrieve the values of an object's properties.
  _.values = function(obj) {
    var values = [];
    for (var key in obj) if (_.has(obj, key)) values.push(obj[key]);
    return values;
  };

As you can see, it just iterates over the keys in the object, and pushes them to an array. So, no, it's not possible to do this without an iteration.

edited Nov 30, 2012 at 18:45

answered Nov 30, 2012 at 18:20

McGarnagle

103k31 gold badges235 silver badges264 bronze badges

Comments

David Hellsing · Accepted Answer · 2012-11-30 18:34:36Z

0

The only way I can think of is JSON:

new RegExp(':\"'+val+'\"').test(JSON.stringify(obj))

Demo: http://jsfiddle.net/J4TDS/

If you are fine with using a function, no need to look in libs, it’s only a few bytes:

function find(o, v) {
    for(var i in o) {
        if (o[i] === v) return true;
    }
}

find(obj, val2);

edited Nov 30, 2012 at 18:34

answered Nov 30, 2012 at 18:11

David Hellsing

109k44 gold badges181 silver badges214 bronze badges

6 Comments

Almo Over a year ago

Doesn't this hide some loops inside the RegExp?

jfriend00 Over a year ago

@David, a regex has a loop to scan through the string. AND, JSON.stringify loops through the object to build the string. This has multiple loops.

Michael Z Over a year ago

@David Hmmm, you have a nice solution. It doesn't matter for me if it inner implementation has loops!

David Hellsing Over a year ago

@MichaelZ if you are fine with writing a function that loops, then you should do that instead. Using JSON comparison like this is not very safe

Selvakumar Arumugam Over a year ago

@MichaelZ If you worried about having the loop inside in your webpage.. then move that code to script file, name it a function and call the function which is same as including a library and calling its function.

|

Collectives™ on Stack Overflow

Find object's value

4 Answers 4

5 Comments

Comments

Comments

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

5 Comments

Comments

Comments

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related