Example of chain of promises

ChainOfPromises.js

var getPromise = (value, delay) => {
  return new Promise(resolve => {
    setTimeout(() => resolve(value), delay);
  });
};

var promise = getPromise('start value', 150);

promise
.then(result => {
  var value = 'step - 1 after ' + result; 
  return getPromise(value, 50);
})
.then(result => {
  var value = 'step - 2 after ' + result; 
  return getPromise(value, 100);
})
.then(result => {
  var value = 'step - 3 after ' + result; 
  return getPromise(value, 150);
})
.then(result => {
  console.log('end result:', result);
});

// Will be printed: 'end result: step - 3 after step - 2 after step - 1 after start value' after some delay