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: stackoverflow.com/questions/2790001/…. — pseudosavant
– pseudosavant, Commented Jan 29, 2013 at 21:45
@pseudosavant Yeah I know. Hope it won't be too much of an issue — gta0004
– gta0004, Commented Jan 29, 2013 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
– pseudosavant, Commented Jan 30, 2013 at 17:31

Naftali · Accepted Answer · 2013-01-29 21:07:02Z

29

Try this instead:

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

edited Jan 29, 2013 at 21:07

answered Jan 29, 2013 at 20:58

Naftali

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6 Comments

Naftali Over a year ago

@gta0004 happy to help ^_^

SLaks Over a year ago

@gta0004: Apparently, name is not an int.

Naftali Over a year ago

@SLaks hehe that is most probably true.

Naftali Over a year ago

@gta0004 output typeof name and your shall see ^_^

cvng Over a year ago

Or, simply cast the key to Int: array.indexOf(+name).

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