Bluebird Promise Example

app.coffee

Promise = require 'bluebird'

getName = ->
  return new Promise((resolve) -> resolve('Luke'))


getAge = (name) ->
  data =
    'Luke': 27

  return new Promise((resolve, reject) ->
    return resolve(data[name]) if data[name]
    return reject(new Error('No matching name found.'))
  )


getUser = (name, age) ->
  data =
    'Luke27': { name: 'Luke', age: 27, fave: 'Mew' }

  return new Promise((resolve, reject) ->
    return resolve(data[name+age]) if data[name+age]
    return reject(new Error('No matching user found.'))
  )

getName()
  .then((name) ->
    console.log(name)
    return getAge(name).then((age) ->
      console.log(age)
      return getUser(name, age)
    )
  )
  .then((user) ->
    console.log(user)
  )
  .catch((e) ->
    console.log(e)
  )

app.js

var Promise = require('bluebird');

function getName() {
  return new Promise(function(resolve) {
    resolve('Luke');
  });
}
function getAge(name) {
  var data = {
    'Luke': 27
  };

  return new Promise(function(resolve, reject) {
    if(data[name]) {
      return resolve(data[name]);
    }
    return reject(new Error('No matching person found.'));
  });
}
function getUser(name, age) {
  var data = {
    'Luke27': {
      name: 'Luke',
      age: 27,
      fave: 'Mew'
    }
  };

  return new Promise(function(resolve, reject) {
    if(data[name+age]) {
      return resolve(data[name+age]);
    }
    return reject(new Error('No matching user found.'));
  });
}

// Get the name
getName()
.then(function(name) {
  console.log(name);
  // Get the age
  // Nested, because we need name to lookup
  return getAge(name).then(function(age) {
    console.log(name + ': ' + age);
    // Get the user
    return getUser(name, age);
  });
})
// Disregard the name & age, as we have the user
.then(function(user) {
  console.log(user);
})
.catch(function(e) {
  console.log(e);
});