rest parameters

1function addition(...nombre) {
2
3    let resultat = 0
4    
5    nombre.forEach(nombre => {
6       resultat+= nombre ;
7    }); 
8
9    console.log(resultat) ;
10    
11}
12
13addition(4 ,9 ,5 ,415 ,78 , 54) ;

1// Before rest parameters, "arguments" could be converted to a normal array using:
2
3function f(a, b) {
4
5  let normalArray = Array.prototype.slice.call(arguments)
6  // -- or --
7  let normalArray = [].slice.call(arguments)
8  // -- or --
9  let normalArray = Array.from(arguments)
10
11  let first = normalArray.shift()  // OK, gives the first argument
12  let first = arguments.shift()    // ERROR (arguments is not a normal array)
13}
14
15// Now, you can easily gain access to a normal array using a rest parameter
16
17function f(...args) {
18  let normalArray = args
19  let first = normalArray.shift() // OK, gives the first argument
20}
21

1function multiply(multiplier, ...theArgs) {
2  return theArgs.map(element => {
3    return multiplier * element
4  })
5}
6
7let arr = multiply(2, 1, 2, 3)
8console.log(arr)  // [2, 4, 6]
9

1function fun1(...theArgs) {
2  console.log(theArgs.length);
3}
4
5fun1();  // 0
6fun1(5); // 1
7fun1(5, 6, 7); // 3
8