how to make function with undefined amount of inputs code example

Example 1: javascript x number of parameters

function display_numbers(...numbers) {
	colors.forEach(function(x) {
  		console.log(x);
	});
}

// call it like:
display_numbers(1)
display_numbers(1, 2, 3, 4)
display_numbers(1, -1, 9, 0, 2)

Example 2: javascript unknown number of parameters

function add (...numbers) {
  let sum = 0;
  for (let i = 0; i < numbers.length; i++) {
    sum += numbers[i]
  };
  console.log(sum);
};

add(2, 3);
add(5, 3, 7, 2);