Alphabetical Ordering

OrderAlphabetical.js

let ingredients = ['Pepper', 'Apples', 'Bananas'];

function sortAlphabetical(array, reverse) {

	// Regex alphabetical characters only.
	const AcceptableCharacters = /^[a-zA-Z ]*$/;

	// Check to see if each item starts with an alphbetical
	// character. If not, then the array isn't vaild.
	array.map((item) => {
		const regexStringIsAlphabetitcal = AcceptableCharacters.test(item.substring(0, 1));

		if (!regexStringIsAlphabetitcal) {
			throw new Error(`sortAlphabetical: Cannot use ${item} to sort an array alphabetically.`);
		}
	});

	// Compare A to B, checking if the alphabetical ordering of
	// each letter for each word is correct.
	array.sort((a, b) => {
		let itemA = a.toLowerCase(),
			itemB = b.toLowerCase();

		if (itemA < itemB) return -1;
		if (itemA > itemB) return 1;
	});

	// Reverse the ordering of the list if true.
	if (reverse) array.reverse();

	return array;
}

console.log(sortAlphabetical(ingredients, false));