Javascript .indexOf not working on an int array

Question

Code:

function showlayer(name){
    var size = js_array.length
    var index = js_array.indexOf(name);
    var plusOne = js_array[index+1];
    document.write("" + name + "<br />" + js_array + "<br />" + index + "<br />" +
                   plusOne + "<br />" )
    ...
}

Output:

301
300,299,301,290,303,304,302,310,291,306,308,305,307,292,294,295,309
-1
300

All possible values of name are in the array, but for some reason indexOf() never finds them. Whats up?

This isn't the problem you are specifically seeing here, but it is worth pointing out that `Array.indexOf()` isn't available on IE8 and lower. See here: http://stackoverflow.com/questions/2790001/fixing-javascript-array-functions-in-internet-explorer-indexof-foreach-etc. — pseudosavant, Jan 29 '13 at 21:45
@pseudosavant Yeah I know. Hope it won't be too much of an issue — gta0004, Jan 29 '13 at 23:47
That stackoverflow link has a polyfill to add support for `Array.indexOf()` to IE6-8 if you need it. I prefer to only support IE9 and up now-a-days, but there are still a lot of IE8 people out there. — pseudosavant, Jan 30 '13 at 17:31

Naftali · Accepted Answer · 2013-01-29T21:07:02.743

29

Try this instead:

...
var index = js_array.indexOf(parseInt(name, 10)); // so that it does not try to compare strings...
...

edited Jan 29 '13 at 21:07

answered Jan 29 '13 at 20:58

Naftali

144,921
39
244
303

@gta0004 happy to help ^_^ – Naftali Jan 29 '13 at 21:04
@gta0004: Apparently, `name` is not an int. – SLaks Jan 29 '13 at 21:07
@SLaks hehe that is most probably `true`. – Naftali Jan 29 '13 at 21:08
@SLaks look at the output. 301 = name. so idk – gta0004 Jan 29 '13 at 21:10
1

@gta0004 output `typeof name` and your shall see ^_^ – Naftali Jan 29 '13 at 21:11
2

Or, simply cast the key to Int: `array.indexOf(+name)`. – cvng Sep 01 '15 at 21:17

Javascript .indexOf not working on an int array

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