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july-meetup

npm

'Contrary to the belief of many, "npm" is not in fact an abbreviation for "Node Package Manager". It is a recursive bacronymic abbreviation for "npm is not an acronym".' - Isaac Z. Schlueter

  • Node Packaged Modules
  • Official package manager for Node.js
  • Now bunlded with Node.js
$ man npm

No manual entry for npm


$ npm foobar

Usage: npm <command>

where <command> is one of:
    add-user, adduser, apihelp, author, bin, bugs, c, cache,
    completion, config, ddp, dedupe, deprecate, docs, edit,
    explore, faq, find, find-dupes, get, help, help-search,
    home, i, info, init, install, isntall, la, link, list, ll,
    ln, login, ls, outdated, owner, pack, prefix, prune,
    publish, r, rb, rebuild, remove, restart, rm, root,
    run-script, s, se, search, set, show, shrinkwrap, star,
    start, stop, submodule, tag, test, tst, un, uninstall,
    unlink, unpublish, unstar, up, update, version, view,
    whoami

npm <cmd> -h     quick help on <cmd>
npm -l           display full usage info
npm faq          commonly asked questions
npm help <term>  search for help on <term>
npm help npm     involved overview

Specify configs in the ini-formatted file:
    /Users/tjkrusinski/.npmrc
or on the command line via: npm <command> --key value
Config info can be viewed via: npm help config

[email protected] /usr/local/lib/node_modules/npm

Now we're getting somewhere.

  • npm commands are simple, most commonly, $ npm install.
  • Packages are installed into a local directory titled node_modules by default.
  • $ npm install express connect will install the latest published versions of express and connect.
  • $ npm install [email protected] will install express at the published version 2.0.0.
  • npm packages typically follow the major.minor.patch sequenced based versioning.
  • $ npm install express --save will install express into your local node_modules directory and list express as a dependency in your package.json.
  • From then on, running $ npm install with no arguments will install or update all dependencies listed in your package.json.
  • $ npm install grunt -g will install grunt in your global npm directory.
  • global npm directory is at (by default) /usr/local/lib/node_modules/.
  • When installing a gloabl package, npm copies the package's bin files to /usr/local/bin.
  • You can easily initiate a package with the $ npm init wizard.
  • Publish packages with the $ npm publish wizard.

package.json

  • Great overview of package.json
  • package.json manages your package or project.
  • Use package.json for any Node.js project, not just public packages.
  • If you don't want to publish the package, just don't run $ npm publish.
  • package.json is the best way to manages dependencies.
  • The scripts object is great for aliasing automated tasks.

{
	"scripts": {
		"test":"mocha tests --timeout 5s --recursive", // run my tests
		"minify":"grunt uglify sass" // minify my client side files
	}
}


$ npm test

> [email protected] test /Users/tjkrusinski/web/package
> mocha tests --timeout 10s --recursive
  • The devDependencies object allows you to not require installing devevelopment specific dependiencies.
  • $ npm install --dev will install the development specified dependencies.
  • $ npm install --saveDev will save the package as a development specific dependency.
  • Use git repos as dependencies "private": "git+ssh://[email protected]:owner/repo.git"

require()

  • require() function that imports modules to the calling module.
  • Scoped locally to the module it is called in.
  • require() takes a single String argument.
  • require() is syncronus, no callbacks involved.
// imports packages
var express = require('express'),
	redis = require('redis');
	
// import relative files
var module = require('./db/connection.js');

// The name of the directory that the currently executing script resides in.
console.log(__dirname);
// /Users/tjkrusinski/Websites/Meetups/july-meetup

// to make sure you absolutely get the file you want.
var module = require(__dirname+'/file.js');
  • Allows access only to objects that are on the exports object in the required module.
  • Does not alter the global process object.
  • Requiring a module once in your project will cache the result and return that from then on from memory.
  • Modify require.cache (Object) to fully reload a module.
  • Personally never encountered having to do this.
  • Use require.resolve() to inspect the file path that require() is going to use.
var module = require(__dirname+'/myModule.js');

delete require.cache[__dirname+'/myModule.js'];

// get a fresh copy
var module = require(__dirname+'/myModule.js');

console.log(require.resolve(__dirname+'/myModule.js'));
// '/Users/tjkrusinski/Websites/Meetups/july-meetup/myModule.js'

exports

  • Allow modules that require() the local modules to access it.

  • exports is an instance of Object.

  • module.exports is a reference to the local module.

  • If you require a module that uses the module.exports object, it returns whatever it is set to, String, Object, Function etc.

  • Using exports

foo.js

exports.foo = 'bar';

bar.js

console.log(require('./foo.js')));
// {foo:'bar'}
  • Using module.exports

foo.js

module.exports = 'bar';

bar.js

console.log(require('./foo.js')));
// 'bar'