AlgoDaily 14: Find First Non-Repeating Character

https://algodaily.com/challenges/find-first-non-repeating-character

This shouldn’t be too hard with a hash map of characters to counts, relying on JavaScript objects having ordered keys to then find the first character with a single occurrence.

function firstNonRepeat(str) {
	const counts = {}
	for (let char of str) {
		counts[char] = counts[char] ? counts[char] + 1 : 1;
	}
	for (let char in counts) {
		if (counts[char] === 1) {
			return char;
		}
	}
	return "";
}