Takes an array of numbers and returns an array of numbers in the original order which represent the percentage each number is of the sum of all of the numbers.

getNumbersPercentageOfSum.js

function getNumbersPercentageOfSum(numbers, decimalPlaces = 2) {
    let total = 0;
    for (const number of numbers) {
        total += number;
    }
    return numbers.map(number => ((number / total) * 100).toFixed(decimalPlaces));
}

getNumbersPercentageOfSum.ts

function getNumbersPercentageOfSum(
	numbers: number[],
	decimalPlaces: number = 2
): string[] {
	let total = 0;
	for (const number of numbers) {
		total += number;
	}
	return numbers.map((number) =>
		((number / total) * 100).toFixed(decimalPlaces)
	);
}