javascript - Multiply all elements in array

Question

I couldn't find an example here what I'm really looking for. I'd like to multiply all array elements, so if an array contains [1,2,3] the sum would be 1*2*3=6; So far I've got this code, but it returns undefined.

function multiply (array) {
    var sum=1;
    for (var i=0; i<array.length; i++) {
        sum = sum * array[i];
    } 
    return sum;
}
console.log(multiply[1,2,3]);

Could anyone please explain, what am I missing here? Thanks in advance!

Answer 1

The cause is already known. Here's an alternative - using Array.reduce for your method:

console.log( [1, 2, 3].reduce( (a, b) => a * b ) );
console.log( Array.from( {length: 20} )
  .map( (v, i) => i + 1 )
  .reduce( (a,b) => a * b )
  .toLocaleString());

// for empty arrays, use some initial value
const arr = [];
if (arr.reduce( (a, b) => a * b, -1 ) === -1) {
  console.error(`The given array ${arr} is empty`);
}