isAnagram via product of prime numbers https://twitter.com/fermatslibrary/status/875340896379817984/photo/1

isAnagram.ts

// https://twitter.com/fermatslibrary/status/875340896379817984/photo/1
const memoizedWords: {
	[Key: string]: number;
} = {};

const ALPHABET_MAPPED_TO_PRIME_NUMBERS: {
	[Key: string]: number;
} = {
	a: 2,
	b: 3,
	c: 5,
	d: 7,
	e: 11,
	f: 13,
	g: 17,
	h: 19,
	i: 23,
	j: 29,
	k: 31,
	l: 37,
	m: 41,
	n: 43,
	o: 47,
	p: 53,
	q: 59,
	r: 61,
	s: 67,
	t: 71,
	u: 73,
	v: 79,
	w: 83,
	x: 89,
	y: 97,
	z: 101,
};

const wordProduct = (word: string) => {
	const lowerCaseWord: string = word.toLowerCase();

	return (
		memoizedWords[lowerCaseWord] ||
		((memoizedWords[lowerCaseWord] = lowerCaseWord
			.split("")
			.reduce(
				(acc, letter) => acc * ALPHABET_MAPPED_TO_PRIME_NUMBERS[letter],
				1
			)),
		memoizedWords[lowerCaseWord])
	);
};

const isAnagram = (wordA: string, wordB: string) => {
	if (wordB === wordA) return false;

	return wordProduct(wordA) === wordProduct(wordB);
};

export { isAnagram };