javascript - For what 0 between comma and bracket is used for?

Question

const sumOfCubes = array => {
    return array.reduce(function(sum,value){
        return sum + Math.pow(value, 3);
    },0) // this line
}

console.log(sumOfCubes([1, 5, 9]));

question from:https://stackoverflow.com/questions/65831727/for-what-0-between-comma-and-bracket-is-used-for

Answer 1

The second argument of the reduce function is the initial value, so for the sum it starts at 0. That's why the ,0) is there for.