using map to start multiple async operations at the same time

parallel-async.js

var Promise = require("bluebird");
var productIds = ["productId1", "productId2", "productId3"];

var getProductsFromDb = function(productId) {
  // returns a promise of product
}

var productPromises = productIds.map(getProductFromDb);

Promise.all(productPromises).then(function(products) {
  // calculate total price here
});