Question

application

In general, one or more programs that are designed to carry out operations for a specific purpose. In the context of Express, a program that uses the Express API running on the Node.js platform. Might also refer to an app object.

API

Application programming interface. Spell out the abbreviation when it is first used.

Express

A fast, un-opinionated, minimalist web framework for Node.js applications. In general, “Express” is preferred to “Express.js,” though the latter is acceptable.

libuv

A multi-platform support library which focuses on asynchronous I/O, primarily developed for use by Node.js.

middleware

A function that is invoked by the Express routing layer before the final request handler, and thus sits in the middle between a raw request and the final intended route. A few fine points of terminology around middleware:

• var foo = require('middleware') is called requiring or using a Node.js module. Then the statement var mw = foo() typically returns the middleware.
• app.use(mw) is called adding the middleware to the global processing stack.
• app.get('/foo', mw, function (req, res) { ... }) is called adding the middleware to the “GET /foo” processing stack.

Node.js

A software platform that is used to build scalable network applications. Node.js uses JavaScript as its scripting language, and achieves high throughput via non-blocking I/O and a single-threaded event loop. See nodejs.org. Usage note: Initially, “Node.js,” thereafter “Node”.

open-source, open source

When used as an adjective, hyphenate; for example: “This is open-source software.” See Open-source software on Wikipedia. Note: Although it is common not to hyphenate this term, we are using the standard English rules for hyphenating a compound adjective.

request

An HTTP request. A client submits an HTTP request message to a server, which returns a response. The request must use one of several request methods such as GET, POST, and so on.

response

An HTTP response. A server returns an HTTP response message to the client. The response contains completion status information about the request and might also contain requested content in its message body.

route

Part of a URL that identifies a resource. For example, in http://foo.com/products/id, “/products/id” is the route.

router

See router in the API reference.