This function sums the given numbers.

sum.ts

/**
 * This function sums the given numbers.
 *
 * @param xs - The array to be calculated
 * @returns The sum of all elements in the number array
 *
 * @example
 * ```typescript
 * sum(); // 0
 * sum([1, 2, 3]); // 6
 * ```
 */
export function sum(...xs: number[]) {
  return xs.reduce((a, b) => a + b, 0);
}