Old School vs. New School: Double for loop vs. a dictionary method for getting the unique values from array.

unique

// old school double loop
// quadratic O(n^2) inefficiency
var unique = function(array) {
    var arr = [],
    	len = array.length;

    for (var idx = 0; idx < len; i++) {
		for(var jdx = i + 1; jdx < len; jdx++) {
			if (array[idx] === array[jdx]) {
				j = ++i;
			}
		}

		arr.push(array[i]);
    }

    return a;
};

// smarter new school
// better for larger arrays
var unique = function(array) {
	var obj = {},
		idx,
		len = array.length,
		res = [];

    for (idx = 0; idx < len; idx += 1) {
    	obj[array[idx]] = array[idx];
    }

    for (idx in obj) {
    	res.push(obj[idx]);
    }

    return res;
};