Imagine we have an array of 10000 promises, how do we process them one by one ?

sequential-promise.js

// Imagine we have an array of 10000 promises,
// How do we process them one by one ?
// Here is a general version g and a recursive version r

let input = [];

for (let i = 1; i <= 10000; i++) {
  input.push(Promise.resolve(i));
}

const g = arr => arr.reduce((p, pnext) => p.then(v => {
  console.log(v);
  return pnext;
}), Promise.resolve(0));

const r = arr => {
  if (arr.length === 1) return arr[0];

  return arr[0].then(v => {
    console.log(v);
    return r(arr.slice(1))
  });
}

g(input).then(val => {
  console.log(val);
});

r(input).then(val => {
  console.log(val);
});

wow so many promises