[ Thanks to Naheed
for this link. ]
“Generally speaking the module name is a path name, but with the
file extension removed. That is, when we write require(‘./simple’),
Node knows to add .js to the file name and load in simple.js.“Modules whose file names end in .js are of course expected to
be written in JavaScript. Node also supports binary code native
libraries as Node modules. In this case the file name extension to
use is .node. It’s outside our scope to discuss implementation of a
native code Node module, but this gives you enough knowledge to
recognize them when you come across them.“Some Node modules are not files in the file system, but are
baked into the Node executable. These are the Core modules, the
ones documented on nodejs.org. Their original existence is as files
in the Node source tree but the build process compiles them into
the binary Node executable.“There are three types of module identifiers: relative,
absolute, and top-level.”