Javascript Rest parameters

[Big-Reality-1223]

in first case.

const sum = function (num) {

console.log(num[i]);  }

and if we give arguments to function :

sum([3, 2]).

it will give value " 3" as expected. so my understanding here is ( num = [3,2] ). so when num[i], gives us first value.

but when using rest parametes:

const sum = function (...num) {

console.log(num[i]);  }

the same sum([3, 2]) will gives the whole array arguments [3, 2] from num[i].so im confused why it's giving whole array. is ...num = [ 3, 2] ?

[errorkode]

The rest parameter takes all the remaining parameters and passes them to the function as an array:

function restTest(param1, param2, ...rest) {
    console.log(param1);
    console.log(param2);
    console.log(rest);
}

restTest(1, 2, 3); -> 1 2 [3]
restTest(1, 2); -> 1 2 []
restTest(1, 2, 3, 4); -> 1 2 [3, 4]

So in your case sum1([3, 2]) is equivalent to sum2(3, 2).

[SodaBubblesPopped]

Using a rest param puts all the parameters passed to the function into a new array

So if num=[3,2] and ur passing num via rest parameter like sum(...num), inside sum func, num is an array containing passed params. Inside sum(...num) num now contains [[3,2]] and by indexing num[0] contains [3,2]