Question

var x = new Array(10);
$.inArray(10,x);
#Returns -1

Fiddle

I’ve come across this weird issue, checking a value in an array with $.inArray, really simple.

But, if the array only has one value in it, inArray returns -1.
If I add another value to the array, it works as expected.

This only happens with integers and not with strings.

What’s going on?!

Answer 1

If you want to create an array with the one number(10) inside you should use bracket literal:

var x = [10];
$.inArray(10,x);

Or with push:

var x = new Array();
x.push(10);

Obviously the first one is more readable and faster to write.

A JavaScript array is initialized with the given elements, except in the case where a single argument is passed to the Array constructor and that argument is a number. Note that this special case only applies to JavaScript arrays created with the Array constructor, not with array literals created with the bracket syntax.

If the only argument passed to the Array constructor is an integer, a new, empty JavaScript array and its length is set to that number
MDN

Fixed fiddle