js2

//----------------------------------------111 1
const comparaison = (a, b) => {
  if (a < b) return -1;
  if (a > b) return 1;
  return 0;
}

//-----------------------------------------222 3
const stringSum = (...numbers) => numbers.reduce((a, x) => a + x, 0).toString();

//-----------------------------------------333 4
const squareAndRectangle = (...args) => {
  if (args.length === 1)
    return args[0] * 4;
  if (args.length === 2)
    return (args[0] + args[1]) * 2;
}

//-----------------------------------------444 13
function calculate(a, b, sign) {
  switch (sign) {
    case '+':
      return a + b;
    case '-':
      return a - b;
    case '*':
      return a * b;
    case '/':
      return a / b;
  }
}

//------------------------------------------555 17
const sumAll = (...args) => args.reduce((a, x) => a + x, 0);