mixedCase.js

/**
 * Create an array containing every possible way to write a given string in mixed-case.
 * 
 * @param {String} str - A string to find every case-combination for.
 * @return {Array} Every possible case-combination.
 */
function mixedCase(str) {
    'use strict';
    str = str.toLowerCase();
    var length = str.length,
        outcomes = Math.pow(2, length),
        limit = Math.pow(10, length),
        zeroes = limit.toString().slice(1),
        outcome = [],
        map,
        out,
        counter;
    while (outcomes--) {
        map = outcomes.toString(2);
        if (map < limit) { map = (zeroes + map).slice(-length); }
        counter = length;
        out = '';
        while (counter--) {
            out = (map[counter] === '1' ? str[counter].toUpperCase() : str[counter]) + out;
        }
        outcome.push(out);
    }
    return outcome;
}