Answers for "Write a function to Sum(numbers, sum) that takes an array of integers and a sum, and returns any two index [i, j] where numbers[i] + numbers[j] === sum. javascript"

sum of all numbers in an array javascript

const arrSum = arr => arr.reduce((a,b) => a + b, 0)

how to find the sum of array using JavaScript

// If you do not want to use array.reduece you can itereate through the array and then get the solution.
const  getSum = (arr)=>{
  let sum = 0;
  for(key of arr){
    sum += key
  }
  return sum
}