Reasons to hate Javascript (2)

Javascript arrays are probably reason enough to keep yourself away from the language, but anyway: sort compares strings by default and ordering an array of numbers will result in something unexpected, unless you provide your own comparison function:

// open firebug console to see the output
var arry = [ 42, 13, 6, 9, 12, 58, 1 ];

// by default it treats the numbers as strings
console.log(arry.sort()) // [1, 12, 13, 42, 58, 6, 9]

// providing a comparison function
console.log(arry.sort(function (a,b) {
        if (a>b) {
                return 1;
        } else {
                if (a<b) {
                        return -1;      
                } else {
                        return 0;       
                }
        }
        // or return a-b
})); // [1, 6, 9, 12, 13, 42, 58]

I don’t know if we could include this in the Javascript arrays are a non-sense box, but it’s definitely an odd behaviour.

Reasons to hate Javascript

The length property in an array:

// check the output on firebug console
var arry = [];

console.log(arry.length); // 0

arry[100] = 'one element';
console.log(arry.length); // 101

for(idx in arry) {
	console.log(arry[idx]);
}
// one element

Yes, the array has only one element and length is showing the largest integer property name in the array, plus one.