Awesome npm resources and tips
npm is a package manager for the JavaScript programming language and comes bundled in the Node.js runtime.
Please read the contribution guidelines before contributing.
npm publish.$ npm install --global npmnpm i → npm installnpm i -D → npm install --save-devnpm t → npm testnpm it →
npm install && npm testnpm r → npm uninstallnpm un → npm uninstallnpm up → npm updateSpeed up your common npm tasks.
In your .zshrc/.bashrc:
alias ni='npm install'
alias nid='npm install --save-dev'
alias nig='npm install --global'
alias nt='npm test'
alias nit='npm install && npm test'
alias nk='npm link'
alias nr='npm run'
alias ns='npm start'
alias nf='npm cache clean && rm -rf node_modules && npm install'
alias nlg='npm list --global --depth=0'By default npm adds packages you install to the
dependencies field in package.json (since v5). You can
prevent this by specifying the --no-save flag. You can add
a package to devDependencies with
--save-dev/-D:
$ npm install --save-dev avaYou can easily run
scripts using npm by adding them to the "scripts" field
in package.json and run them with
npm run <script-name>. Run npm run to
see available scripts. Binaries of locally install packages are made
available in the PATH, so you
can run them by name.
{
"name": "awesome-package",
"scripts": {
"cat": "cat-names"
},
"dependencies": {
"cat-names": "^1.0.0"
}
}$ npm run cat
MaxAll package.json properties are exposed as environment variables:
{
"name": "awesome-package",
"scripts": {
"name": "echo $npm_package_name"
}
}$ npm run name
awesome-packageYou can pass options to the command you are using in your npm script
by adding -- --flag like in the example below. The
-- marks
the end of options parsing, so npm run will just ignore
it and pass it to the command.
{
"name": "awesome-package",
"scripts": {
"xo": "xo",
"xo:fix": "npm run xo -- --fix",
}
}Adding the -- --fix option is like executing
xo --fix.
npm run has a --silent option which is
especially useful when combining npm scripts.
Imagine you have a setup for linting your JavaScript files like the following:
{
"name": "awesome-package",
"scripts": {
"xo": "xo",
"xo:fix": "npm run xo --silent -- --fix",
}
}Using the --silent option reduces the output in the
terminal. See this
comparison.
npm comes with predefined lifecyle scripts which are excuted under specific conditions if they are defined in your package.json.
{
"name": "awesome-package",
"scripts": {
"prepublishOnly": "nsp check"
},
"devDependencies": {
"nsp": "^3.0.0"
}
}This will be executed automatically before your npm package is
published to the registry via npm publish to check for
known vulnerabilties in your dependencies.
Note: prepublishOnly is available since npm v4.0.0. See npm docs.
npm start and
npm testnpm start and npm test are also lifecycle
scripts but are not executed automatically.
{
"name": "awesome-package",
"scripts": {
"start": "node server.js",
"test": "ava"
},
"devDependencies": {
"ava": "^1.0.0"
}
}Therefore they can be executed simply with:
$ npm test
$ npm startpre and post
scriptsThese are special lifecycle scripts which can be used to run scripts automatically in sequence.
{
"name": "awesome-package",
"scripts": {
"pretest": "eslint .",
"test": "ava"
},
"devDependencies": {
"eslint": "^4.19.0",
"ava": "^1.0.0"
}
}$ npm testThis will lint your files before running your tests. The tests will not run if linting fails. Or more generally spoken: the following script won’t be executed if one of the scripts running in sequence exits with an exit code other than 0.
Note: pre and post scripts can also be
used for your custom npm scripts. So npm run foo will also
run prefoo and postfoo if defined.
npxnpm comes
bundled with npx (Since v5.2.0) — a tool to execute
package binaries. Each command is executed either from the local
node_modules/.bin directory, or from a central cache,
installing any packages needed in order for <command>
to run.
{
"name": "awesome-package",
"dependencies": {
"cat-names": "^1.0.0"
}
}If the binary is already installed, it will be executed from
node_modules/.bin.
$ npx cat-names
MaxBut if the binary is missing, it will be installed first.
$ npx dog-names
npx: installed 46 in 3.136s
BentleyWith npx (Comes bundled with npm v5.2.0 or newer) and
the node-bin
package, you can easily try out code in different Node.js versions
without having to use a version manager like nvm, nave, or n.
$ npx --package=node-bin@6.11.0 -- node --version
v6.11.0Sometimes it can be useful to have a local version of a package as a
dependency. You can use npm link to link one local package
into another. Run npm link in the package you want to use.
This creates a global reference. Then go into your original package and
run npm link <package-name> to link in the other
package.
$ cd rainbow
$ npm link
$ cd ../unicorn
$ npm link rainbowYou can now use rainbow as a dependency in the
unicorn package.
npm supports using a shorthand for installing a package directly from a GitHub repo:
$ npm install sindresorhus/chalkLet’s target a specific commit as the main branch is a moving target:
$ npm install 'sindresorhus/chalk#51b8f32'Specify either a commit SHA, branch, tag, or nothing.
You can also install Git dependencies with semver: (Requires npm v5 or newer)
$ npm install 'sindresorhus/chalk#semver:^2.0.0'$ npm install chalk@1.0.0$ npm ls --depth=0Get help docs for a command:
$ npm help <command>Example:
$ npm help installQuickly get a standalone version of a package that is browserified and usable in the browser.
https://wzrd.in/standalone/<package-name>[@<version>]Examples:
Great for prototyping, but download the file or use Browserify yourself for production.
^ mean in package.json versioning?