getCode.js

function getCodes (charset, codeLength, codeCount) {
	var codeList = [],
		codeListLength = 0,
		charsetLength = charset.split('').length,
		codePerCharset = charsetLength / codeLength,
		collision = 0,
		i, temp;
	
	while (codeListLength < codeCount) {
		var charsetCopy = charset.slice(0).split('');
		
		for (i=charsetLength - 1; i > 0; i--) {
			var j = Math.floor(Math.random() * (i + 1));
			
			temp = charsetCopy[i];
			charsetCopy[i] = charsetCopy[j];
			charsetCopy[j] = temp;
		}
		
		charsetCopy = charsetCopy.join('');
		for (i=0; i<codePerCharset && codeListLength<codeCount; i++) {
			temp = charsetCopy.substr((i * codeLength), codeLength);
			
			if (codeList.indexOf(temp) == -1) {
				codeList.push(temp) && codeListLength++;
			}
			else {
				collision++;
			}
		}
	}
	
	console.log(collision);
	
	return codeList;
}