JS function: get all word permutations of a given length over a given alphabet

permute.js

// get all words of a certain length in alphabet
function permute(alphabet, wordLength) {
	if (wordLength === 0) return [''];
	var words = [];
	var shorterWords = permute(alphabet, wordLength - 1);

	for (var i = 0; i < alphabet.length; i++) {
		for (var j = 0; j < shorterWords.length; j++) {
			words.push(alphabet[i] + shorterWords[j]);
		}
	}
	return words;
}

console.log(permute('ab', 4).join('\n'));