README.md

Run with the following bash command

ts-node computeJoinPoint.ts

computeJoinPoint.ts

function getDigitsTotal(x: number): number {
	let total = 0;

	while (x > 0) {
		total += x % 10;
		x = Math.floor(x / 10);
	}

	return total;
}

function computeJoinPoint(s1: number, s2: number): number {
	let sum1 = s1,
		sum2 = s2;

	while (sum1 !== sum2) {
		sum1 += getDigitsTotal(sum1);
		sum2 += getDigitsTotal(sum2);
	}

	return sum1;
}	

console.log(computeJoinPoint(471, 480));