Use reduce to sum all values of an array passed via a console log

user_3872557 0
Viewed 47

I'm trying to get the total of an array passed via a console log. However instead of adding the numbers it's returning the array with a 0 in front.

This is what I have tried

const sum2 = (array) => {
  let total = 0;
  const totalFigure = array.reduce((total, number) => {}, 0)
  return total + array
}

console.log(sum2([1, 3, 5, 7, 9]));

javascript
2 Answers

Since you are not doing anything to reduce your array in that function

(total, number) => {}

and your initial value is 0, you are just adding 0 to your array by returning

total + array

You are never summing up your array. total + array turns into 0 + array.toString() which creates the 01,3,5,7,9 you are seeing.

If you want to sum up the values of you array, this is one approach:

const sum2 = (array) => array.reduce((total, number) => total+=number, 0)

console.log(sum2([1, 3, 5, 7, 9]));

(total, number) => total+=number

this increments the initial value (which total is first set to) by number, adding them together and returning them to the next iteration of the reduce function

user_66345910

Array.prototype.reduce() accepts callback function where the first parameter of the callback is "total" value calculated in previous iteration of loop and current value of iteration as the second parameter. The final code could look like this:

const sum2 = arr => {
  const result = arr.reduce((total, number) => {
    return total + number;
  }, 0);

  return result;
};

And shorter:

const sum2 = arr => arr.reduce((total, number) => total + number, 0);
user_36135050
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