Glossary
application
In general, one or more programs 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. May also refer to an app object.
API
Application programming interface. Spell out on first use.
Express
A fast, un-opinionated, minimalist web framework for Node.js applications. In general, prefer simply “Express” to “Express.js,” though the latter is acceptable.
libuv
Multi-platform support library with focus on asynchronous I/O, primarily developed for use by Node.js.
middleware
A function 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 statementvar 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
Software platform 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 an response. 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 may 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.
