Tell us what's happening

Tell us what’s happening:777

Your code so far

const sum = (function() {
  "use strict";
  return function sum(... z) {
    return z.reduce((a,b,...z) => a + b, 0);
console.log(sum(1, 2, 3)); // 6

how can i do this " The sum function uses the ... spread operator on the args parameter."
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Link to the challenge:

sum is a self invoking function which returns an anonymous function that accepts nth amount of parameters.

The returned anon function returns the value from a reduce method that starts from index 0
a is the accumulator, b is the current value being iterated, and the third parameter ...z is the passed parameters in array form.

thanks i understand now