untitled notebook

var PromisePool = require('promise-debounce-pool'); // create a promise resolver function for // each of your expensive operations var expensiveFooOperation = function(resolve, reject) { setTimeout(function() { resolve('foo data ' + Math.random()) }, 1000); }; var expensiveBarOperation = function(resolve, reject) { setTimeout(function() { resolve('bar data ' + Math.random()) }, 1000); }; // create an instance of the pool var promisePool = new PromisePool(); // associate each promise resolver to a key in the pool // Note: the functions are not invoked at this point promisePool.set('foo', expensiveFooOperation); promisePool.set('bar', expensiveBarOperation); // make multiple calls var fooCall1 = promisePool.get('foo') //starts a new foo promise .then(function(fooData) { console.log('fooCall1: ' + fooData); }); var fooCall2 = promisePool.get('foo') //returns the same pending foo promise (fooCall1) .then(function(fooData) { console.log('fooCall2: ' + fooData); //same data from fooCall1 }); var barCall1 = promisePool.get('bar') //waits until fooCall1 promise resolved/rejected then creates a new bar promise .then(function(barData) { console.log('barCall1: ' + barData); }); var barCall2 = promisePool.get('bar') //returns the same pending bar promise (barCall1) .then(function(barData) { console.log('barCall2: ' + barData); // same data from barCall1 }); setTimeout(function() { var fooCall3 = promisePool.get('foo') //starts a new foo promise (since previous fooCall1 promise has now resolved) .then(function(fooData) { console.log('fooCall3: ' + fooData); // data from new fooCall3 promise }); var barCall3 = promisePool.get('bar') //returns the same fooCall1 promise from before, its still pending .then(function(barData) { console.log('barCall3: ' + barData); // same data from barCall1 }); }, 1500);