MEAN Architecture Demystification
MEAN is a software stack for building active websites and web applications. It is a collection of JavaScript-based technologies for developing web applications. Thus, from the client to the database, everything is based on JavaScript. This free and open source stack is an acronym that's made up of the first letters of MongoDB, Express.js, Angular.js, and Node.js, as shown here:
https://github.com/linnovate/mean/wiki/Built-with-Mean.
Before going into MEAN application development, we will briefly discuss the individual technologies that make up the MEAN stack. We will start with MongoDB.
MongoDB
MongoDB is a document-oriented database program. The database, which is classified as NoSQL, is developed by MongoDB Inc. It's a free and open source database that uses JSON-like documents with schemas. Described here are some of the major features that make MongoDB stand out in application development:
Strong consistency: Strong consistency is a default feature in MongoDB, and thus it takes no additional upgrades to create consistency. It's also highly guaranteed: as long as a write is successful, you will be able to read it. Automatic failover of the replica set makes it highly available. Also, flexibility and scalability are not readily available in traditional databases that only rely on a defined schema. In comparison, MongoDB, which is NoSQL, relies on the key-to-value pair approach. This enables flexibility and scalability in MongoDB.
Real-time aggregation: This is a built-in MongoDB feature that allows real-time statistical analysis and the generation of pre-aggregated reports on request.
Ad hoc queries: These are impromptu queries that are written to extract information from the database, but only when necessary.
Indexing: Indexing in MongoDB makes it easy to search documents without performing a collection-wide scan by matching specific queries with documents.
Database-as-a-service: Database-as-a-service offerings by MongoDB enable users to access databases without having to install software or set up hardware. MongoDB Atlas, which is a cloud-hosted service offering by MongoDB Inc., will be used in this book. As we progress in the next chapter, we will go through all the processes involved in its setup.
Note
For more features and pricing information on different tiers, refer to this link: https://github.com/angular/blob/master/CHANGELOG.md.
However, you should be aware that no web framework is perfect, and in the case of Angular, its verbosity and complexity renders it a difficult framework to master. Furthermore, Angular has a steep learning curve.
In this section, we introduced the third component of the MEAN stack – Angular. We discussed its features, as well as its limitations. In the next section, we will introduce our final MEAN component, a server-side technology known as Node.js.
Node.js
Node is an open source program that is built on a JavaScript runtime engine (Chrome's V8) and consists of JavaScript libraries that are implemented in the form of modules. The cross-platform server environment is lightweight and efficient because it uses an event-driven, non-blocking I/O model. For example, PayPal employs Node to solve the problem that arises owing to the boundary between the browser (client side) and server (server side) by enabling both to be written in JavaScript. This, in turn, helps PayPal unify their engineering specialties into one team, thus enabling them to focus on user needs and create solutions to meet these on the technology stack level. Some other websites and applications built on Node are eBay, GoDaddy, Groupon, Uber, Netflix, Mozilla, Yahoo, LinkedIn, and so on. The outstanding performance offered by Node makes it the heart of the MEAN stack. According to a number of benchmarks, JavaScript technology for the backend outperforms several other backend programming languages, such as PHP, Python, and Ruby. Listed here are some of the major advantages of Node:
Fast code execution: Google Chrome's V8 JavaScript engine makes the Node library extremely fast at code execution as V8 compiles JavaScript into native machine code.
Single-threaded operation: Node is able to handle concurrent tasks because its architecture is built to use the single-threaded event loop model.
Highly Scalable: Its microservice architecture makes Node highly scalable, thereby making it a highly sought after development environment by most start-ups and established companies alike.
Asynchronous and event-driven I/O: Programs in Node do not run until an event occurs.
Open source (MIT license) and community support: Node is a distributed development project that is governed by the Node.js Foundation. Also, Node has a very active and vibrant community with several code files shared by GitHub users.
Easy web-application deployment: Node allows the automated deployment of web applications. Also, the deployment of further updates can be reduced to a single command with Node. Thus, the deployment of Node applications has also led to the proliferation of Platform-as-a-service (PaaS) providers such as Heroku, Modulus, and so on.
Easy scalability: Developers find it easy to scale applications horizontally as well as vertically.
However, you should be aware of a few points before beginning application development in Node. Using relational databases in conjunction with Node might be a daunting task because Node does not provide support for them. Also, using Node is unsuitable for heavy-computation applications. Having given an overview of Node, we will now progress and build our first Node application in the next section.
Note
A detailed introduction to Node, implementing node features, and various activities will be covered in future chapters.
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