NPM

Components: website, registry, command line (CLI)

Website: discover package, setup profile

Registry: package database

CLI:

• get packages

• get standalone tools

• run without download with npx

• ...

Install

Install node.js

npm install npm@latest -g.

nvm - version manager

Prevent Permission Errors

EACCES - permission errors

Install packages

Install

• locally

  • when to depend from own module for 'require',

  • npm install

    • npm install --save //- add to package.json as dependency

    • npm install --save-dev // add as devDependency

  • will install into node_modules dir

  • version

    • if package.json exists, the latest version that satisfies the semver rule

      • product.feature_not_breaking_existing_features.bugfix

    • or latest

  • npm uninstall //- remove

  • npm uninstall --save xxx //- remove from the dependencies in package.json

• globally

  • command line tool, install globally "npm install -g xxx"

  • NEVER "sudo", see https://medium.com/@ExplosionPills/dont-use-sudo-with-npm-still-66e609f5f92

  • For tools, project level installation preferred over global installation, use npx (or yarn) to run locally installed packages

  • For global installation, use npm's 'prefix' configuration, (see npm help 7 config)

    • $ npm config set prefix ~/.npm

    • Or just edit ~/.npmrc and include 'prefix=~/.npm'

    • Also add the bin path

Package.json

"npm init" creates the file

• name: all lower case, no space, - & _ allowed

  • scoped: "@scope/name"

  • only scope owner can publish something under scope

  • install under a sub folder in scope folder

  • use require("@scope/name")

• version: x.x.x

• description

• main: always index.js

• scripts : by default an empty test script

• keywords :

• author

• license

• bugs

• homepage

• dependencies - required in production

• devDependencies - needed for development and testing

Update Local package

npm update

npm outdated - check

npm update -g xxx

npm outdated -g --depth=0

npm install npm@latest -g

npm uninstall -g xxx

Create Node.js modules

Package & Module

• package

  • file or dir or zip or git...

  • contains package.json

  • most packages are also modules

• module

  • can be loaded by Node.js require(...)

  • can be

    • a folder with package.json that contains a main field

    • folder with an index.js inside

    • a javascript file

  • the node_modules folder is the place node.js looks for a module

To create module

1. npm init //- create package.json

2. create index.js

   1. write export.someThing = something

3. create a test.js which requires the package and test

Publish a module

Policy - be respectful

Create user account : npm adduser

or login : npm login

(npm whoami)

Review everything in the package directory. All will be included unless in .gitignore or .npmignore

Choose a name: unique, not already owned, not spelled like another, not misleading, not offensive

Documentation: readme.md

npm publish

Working Locally

Workspace: https://docs.npmjs.com/cli/v7/using-npm/workspaces

Pack: npm pack

Link: npm link

Version Range Comparator

• Comparator = operator + version:

  • < <= > >= =

  • Can be joined:

    • by whitespace (intersection)

    • by || union

• Advanced syntax:

  • huphen range X.Y.Z - A.B.C : >=X.Y.Z <=A.B.C

  • x-range (x, X, *): match any

  • tilde range ~ (match and greater)

    • ~1.2.3 := >=1.2.3 <1.3.0

    • ~1.2 := >=1.2.0 <1.(2+1).0 := >=1.2.0 <1.3.0

    • ~1 := >=1.0.0 <(1+1).0.0 := >=1.0.0 <2.0.0

  • caret ranges ^:

    • allows patch and minor updates for versions 1.0.0 and above, patch updates for versions 0.X >=0.1.0, and no updates for versions 0.0.X.

    • reason: 0.x version treated x as "breaking change"

• Pre-release tags

  • Only allowed if comparator has the same tag