rest operator vs spread syntax in js

dengan rest operator(…) kita boleh set di function parameter untuk jadi kan unlimited array of anything. so dia takder fixed size array. tapi benda ni hanya boleh di pakai sebagai function parameter!

// rest operator
const tambah = (...semua) => {
    let kira = 0;
    for(const x of semua){
        kira += x;
    }
    return kira;
}


console.log(tambah(1,3,45,6,8,9,99)); // could be longer

boleh baca kat sini

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters

dan spread operator syntax , kita boleh jadinya iterable contohnya array di atas expand ke array yg baru.

contoh:

// rest operator ...
const tambah = (...semua) => {
    let kira = 0;
    for(const x of semua){
        kira += x;
    }
    return kira;
}

const arr1 = [100];

console.log(tambah(1,3,45,6,8,9,99));
// expect 171
console.log(tambah(1,3,45,6,8,9,99, ...arr1)); //spread syntax ...
// expect 271

boleh baca kat sini.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax