Using indexOf() in Javascript array

Question

I have an array like this [HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"]. I got this from console.

I trying to find out value like below

var sku = skus_colorcode.indexOf('9620');                   
console.log(sku);

But it is returning -1.

Why I am getting this result ??

.indexOf looks only at numeric indices. Your Array has been populated with non-numeric properties, which will be ignored. So the question would be why an Array is being used this way in the first place. — user1106925
– user1106925, Commented Jul 2, 2016 at 15:58
This is invalid array syntax. If you modify it to an object, you can use ES6 methods to get the key: Object.entries(skus_colorcode).find(a => a[1] == "9620")[0]. — Sebastian Simon
– Sebastian Simon, Commented Jul 2, 2016 at 16:01
I think the OP made it sufficiently clear that the syntax shown is the output from a console, which isn't required to represent data as valid JS syntax. — user1106925
– user1106925, Commented Jul 2, 2016 at 16:07

ClementNerma · Accepted Answer · 2016-07-02 16:01:08Z

4

You code is not valid at all. An array is a list of elements, without keys. You must use an object, like this :

var skus_colorcode = {HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"}

To find the key (HT....) that corresponds to "9620", try this code :

var keys = Object.getOwnPropertyNames(skus_colorcode), key;

for(var i = 0; i < keys.length; i++)
    if(skus_colorcode[keys[i]] === "9620") {
        key = keys[i];
        break;
    }

// The right key is into the "key" variable
console.log(key); // says "HT2787Z2UK"

answered Jul 2, 2016 at 16:01

ClementNerma

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6 Comments

user1106925 Over a year ago

An array can hold non-numeric keys and be perfectly valid. The syntax shown wouldn't be a valid initializer, but that's clearly not the actual syntax the OP used to construct the array.

ClementNerma Over a year ago

On my browser (latest version of Chrome) the array cause a syntax error

user1106925 Over a year ago

"...The syntax shown wouldn't be a valid initializer, but that's clearly not the actual syntax the OP used to construct the array"

user1106925 Over a year ago

var a = []; a.foo = "bar"; console.log(a.foo); // bar

ClementNerma Over a year ago

Yes, that syntax works, but not the array given in the question : [HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"] And an array is made to accept only numerical indexes, for other indexes you have to use an object.

|

hemnath mouli · Accepted Answer · 2016-07-02 16:01:06Z

1

Try this

function arraySearch(arr,val) {
    for (var key in arr) {
        this_val = array[key];
        if(this_val == val){
            return key;
            break;
        }
    }
 }

answered Jul 2, 2016 at 16:01

hemnath mouli

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3 Comments

ClementNerma Over a year ago

Your code has a big problem : Using a for(var ...) loop is VERY slow. You should use Object.keys(arr); and next do an incremental loop like I did to search through the array.

user1106925 Over a year ago

@ClementNerma: How do you think Object.keys is able to collect the keys? Object.keys also has to perform a .hasOwnProperty() check on each key. Did you actually test the performance?

ClementNerma Over a year ago

Yes I've tested the performances. Object.keys() does not perform a .hasOwnProperty() because it's a C++ native function. So execution is faster than a JavaScript code. Strangely, for(var i in ...) is one of the slower way to explore an object. NOTE : I did an error that's not Object.keys() but Object.getOwnPropertyNames().

Piyush.kapoor · Accepted Answer · 2016-07-02 16:05:03Z

0

This should be

   var obj = {HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"}

for (var key of obj) {
  if (obj[key] == "9620"){
     return key;
  }
}

return false

answered Jul 2, 2016 at 16:05

Piyush.kapoor

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Comments

tatactic · Accepted Answer · 2016-07-02 20:04:51Z

I agree with "hemnath mouli" code should be like as he wrote:

<script type="text/javascript">
    keys = {HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"};
    function getIndexOf(obj,value){
        var count = 0;
        for (var i in obj){
            if(obj[i] == value.toString()){
                return  "index[" + count + "]:" + obj[i]  + " = " + i;
                //return what you want
            }
            count ++;
        }
    }
</script>

Then U got the values

<script type="text/javascript">
    alert(getIndexOf(keys,9621));
</script>

Could you please send a piece of code to retrieve the values @ClementNerma even I agree with you this is not the more efficient way.

I just do not want to "downvote" the question.

Or if you want to convert your Object to an Array:

<script type="text/javascript">
    keys = {HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"};
    function obj2Array(obj){
        k = [];
        for (var i in obj){
            k.push(obj[i]);
        }
        return k;
    }
</script>

<script type="text/javascript">
    arr = obj2Array(keys);
    alert (arr[2]);
</script>

@abu abu

MHS · Accepted Answer · 2016-07-02 16:04:42Z

-2

You can use Jquery:

var skus_colorcode = {HT2787UK: "9618", HT2787Z1UK: "9619", HT2787Z3UK: "9621", HT2787Z2UK: "9620"}


$.each( skus_colorcode , function( key, value ) {
   if(value == '9620')
       alert(key);
});

answered Jul 2, 2016 at 16:04

MHS

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