Book Image

The Node Craftsman Book

By : Manuel Kiessling
Book Image

The Node Craftsman Book

By: Manuel Kiessling

Overview of this book

The Node Craftsman Book helps JavaScript programmers with basic Node.js knowledge to now thoroughly master Node.js and JavaScript. This book dives you deeper into the craft of software development with Node.js and JavaScript, incuding object-orientation, test-driven development, database handling, web frameworks, and much more. The Node Craftsman Book shows you how to work with Node.js and how to think deeply about how you build your Node projects. You'll master how to build a complete Node.js application across six crafting milestones, and you'll learn many specific skills to achieve that mastery. These skills include how to work with the Node Package Manager in depth, how to connect your Node applications to databases, and how to write unit tests and end-to-end tests for your code. You'll experience the full Node.js development picture, and learn how to craft and control your Node.js applications - right through to fully-fledged web applications using REST, and integration with Angular applications.
Table of Contents (17 chapters)
Free Chapter
1
Part 1: Node.js Basics in Detail
2
Working with NPM and Packages
3
Test-driven Node.js Development
11
Milestone 1 – A First Passing Test Against the Server
13
Milestone 3 – Setting the Stage for a Continuous Delivery Workflow

Querying collections efficiently

When retrieving large result sets from a MongoDB collection, the same rule that applies to MySQL database result sets also applies here: reading the complete result set into our Node.js process at once isn't going to be efficient resource-wise. Handling a result array with 2,000,000 entries will eat a lot of memory no matter what. This is what the toArray method, which we used until now, does:

collection.find().toArray(function (err, documents) { 
  // We now have one large documents array 
});

What collection.find() returns is a so-called cursor object. It can be transformed into an array, which is very convenient, but when handling lots of documents, it's better to handle each one separately using the cursor's each method:

collection.find().each(function (err, document) { 
  // We retrieve one document with each callback invocation 
});

This way, the cursor object...