use reduce method to sum up the array code example

Example 1: js sum of array

[1, 2, 3, 4].reduce((a, b) => a + b, 0)

// Output: 10

Example 2: javascript reduce

var array = [36, 25, 6, 15];

array.reduce(function(accumulator, currentValue) {
  return accumulator + currentValue;
}, 0); // 36 + 25 + 6 + 15 = 82

Example 3: array reduce

arr.reduce(callback( accumulator, currentValue[, index[, array]] ) {
  // return result from executing something for accumulator or currentValue
}[, initialValue]);