Async Waterfall in JavaScript

asyncWaterfall.js

function selectMovie(input, callback) {
  const output = `Movie Selected: ${input} ->`;
  callback(null, output);
}

function bookTicket(input, callback) {
  const output = `${input}, Ticket ID: 1234 ->`;
  callback(null, output);
}

function watchMovie(input, callback) {
  const output = `${input} Watching Movie ->`;
  callback(null, output);
}

// Utility function for waterfall behaviour
async function waterfall(water, input, callback) {
  let result = input;
  for (let i = 0; i < water.length; i++) {
    result = await new Promise((resolve, reject) => {
      water[i](result, (err, result) => {
        if (err) reject(err);
        else resolve(result);
      });
    });
  }

  callback(null, result);
}

// series execution, passing the result of one function to the next and finally getting the result...
waterfall([selectMovie, bookTicket, watchMovie], "2020", (err, result) => {
  console.log(`${result}, Finished watching movie in waterfall...`);
});