About reduce() function

JavaScript
1

https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/es6/use-the-rest-parameter-with-function-parameters
const sum = (…args) => {
return args.reduce((a, b) => a + b, 0);
}

My only doubt is why do we add the ‘0’ at the end

2

It’s initial value, think about the below. Go to the MDN maybe, there are bunch of examples.

const sum = (...args) => {
return args.reduce((a, b) => a + b, 0);
}


console.log(sum(2,3));//5


const sum1 = (...args) => {
return args.reduce((a, b) => a + b, 1);
}


console.log(sum1(2,3));//6
3

Ok thanks :+1:
Got it!

5

But this task requires 0 to solve it.
?

6

Yup, I believe that’s because of the testcase: sum()

const sum = (...args) => {
  
  return args.reduce((a, b) => a + b);
}
console.log(sum());

/*
TypeError: Reduce of empty array with no initial value
    at Array.reduce (<anonymous>)
.......
*/
8

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