async pair adder

adder

simple async summer 

gistfile1.js

async function remoteExecutor(a, b) {
  return Promise.resolve(a + b)
}

async function sum(arr) { 
   
  while (arr.length !== 1) {

    let result = []

    for(let i = 0; i < arr.length - 1; i += 2) {
      result.push(remoteExecutor(arr[i], arr[i + 1]))
    } 
    if (arr.length % 2) {
      result.push(arr[arr.length - 1])
    }
    
    arr = await Promise.all(result)
  }

  return arr[0]
}