Get index of array of objects via jquery

Question

I have the following array:

var = array[
            {"id" : "aa", "description" : "some description"},
            {"id" : "bb", "description" : "some more description"},
            {"id" : "cc", "description" : "a lot of description"}]

and I try to find the index of the array that contains the id === "bb". The solution I came up with is the following:

var i = 0;
while(array[i].id != "bb"){
   i++;
}
alert(i) //returns 1

Is there an easier way that has cross-browser functionality? I tried $.inArray(id,array) but it doesn't work.

Easier? What part of that isn't already easy? (though you should add some validation to make sure the id exists) — musefan
– musefan, Commented Oct 1, 2013 at 8:20
I know I just think I have to avoid loops as much as possible ;) So I thought maybe there's a way.... Good point with the validation. A simple try/catch should do the job, right? — FLuttenb
– FLuttenb, Commented Oct 1, 2013 at 8:26
No need for try/catch. Just use a for loop instead of while and use -1 as the result if none is found - that seems to be common. I'll do you an answer I think — musefan
– musefan, Commented Oct 1, 2013 at 8:27

musefan · Accepted Answer · 2013-10-01 08:31:52Z

5

I don't see any problem with the complexity of your code, but I would recommend a couple of changes including adding some validation in case the value does not exists. Further more you can wrap it all in a reusable helper function...

function getArrayIndexForKey(arr, key, val){
    for(var i = 0; i < arr.length; i++){
        if(arr[i][key] == val)
            return i;
    }
    return -1;
}

This can then be used in your example like so:

var index = getArrayIndexForKey(array, "id", "bb");
//index will be -1 if the "bb" is not found

Here is a working example

NOTE: This should be cross browser compatible, and will also likely be faster than any JQuery alternative.

answered Oct 1, 2013 at 8:31

musefan

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1 Comment

mowgli Over a year ago

This is buggy when refreshing browser. Need to refresh twice to get updated true index

Labu · Accepted Answer · 2016-04-07 17:03:19Z

2

var myArray = [your array];
var i = 0;

$.each(myArray, function(){
    if (this.id === 'bb') return false;
    i++;
})

console.log(i) // will log '1'

Update with modern JS.

let index
myArray.map(function(item, i){
    if (item.id === 'cc') index = i
})

console.log(index) // will log '2'

edited Apr 7, 2016 at 17:03

answered Oct 1, 2013 at 8:30

Labu

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Comments

Thirumalai murugan · Accepted Answer · 2013-10-01 08:29:48Z

1

inArray can't work with multidimensional array so try like the following

var globalarray= [
            {"id" : "aa", "description" : "some description1"},
            {"id" : "bb", "description" : "some more description"},
            {"id" : "cc", "description" : "a lot of description"}];
var theIndex = -1;
for (var i = 0; i < globalarray.length; i++) {
    if (globalarray[i].id == 'bb') {
        theIndex = i;
        break;
    }
}
alert(theIndex);

Demo

answered Oct 1, 2013 at 8:29

Thirumalai murugan

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Comments

Chokchai · Accepted Answer · 2013-10-01 08:30:04Z

1

You can use jQuery.each - http://api.jquery.com/jQuery.each/

var i;
jQuery.each(array, function(index, value){
   if(value.id == 'bb'){
      i = index;
      return false; // retrun false to stop the loops
   }
});

answered Oct 1, 2013 at 8:30

Chokchai

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Comments

rink.attendant.6 · Accepted Answer · 2015-07-14 05:43:36Z

0

Object.keys(yourObject).indexOf(yourValue);

edited Jul 14, 2015 at 5:43

rink.attendant.6

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answered Jul 14, 2015 at 5:39

Andrii Skreka

1

1 Comment

Lawrence Aiello Over a year ago

Please add an explanation so the OP understands why this code solves his problem.

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