Npm and npx are essential tools for productive JavaScript development in 2023. However, if you‘re new to Node.js, understanding the differences between these two command line utilities and when to use each can be confusing.
As an experienced JavaScript engineer who relies on both npm and npx daily, let me clearly break down what each does, key distinctions, use cases, best practices, and actionable recommendations so you can leverage them like a pro!
An Overview of Npm and Npx
First let‘s define what we mean by npm and npx at a basic level:
Npm – Short for "Node Package Manager". Npm is first and foremost a repository of 1.3+ million open source JavaScript packages located at npmjs.com. The npm CLI (command line interface) allows you to install packages from this registry and manage dependencies in projects locally.
Npx – Short for "Node Package Execute". Npx comes bundled with the npm CLI and allows executing JavaScript code from npm packages temporarily without installing them.
Together they form a robust system for easily building Node applications using community JavaScript libraries.
A Brief History
Before jumping into usage differences, some quick history…
Npm‘s 1.0 release came in January 2010 from creator Isaac Z. Schleuter as a much needed dependency and package management ecosystem for Node.js development. It quicky became indispensable for JavaScript projects.
Over 7 years later in January 2017, Isaac Z. Schleuter released npx as an official extension to the npm CLI aiming to improve the developer experience running CLI tools and scripts in Node. Npx eliminated much of npm‘s friction for one-off execution use cases.
Since launching, npm has grown its package registry to over 2 million submissions and npx usage has skyrocketed. The two tools that once started as a package manager and convenient wrapper have grown into an essential part of the JavaScript development experience.
Let‘s hear perspectives from Isaac Z. Schleuter, npm and npx‘s creator, on their origins:
"Developing npm was an opportunity that fell in my lap to make an impact and solve real problems I was struggling with while building JavaScript apps…The goal of npx was improving discoverability for CLI tools published to npm by removing friction of installation"
With background context covered, let‘s get hands on with some code and understand these power tools even better!
Key Differences Between Npm and Npx
While npm and npx offer complimentary value, their approach and functionality differ across a few key areas:
Installing Packages:
// npm installs all dependencies locally
npm install lodash
// npx fetches packages on-demand
npx lodashNpm persists packages…npx is temporary.
Executing Commands:
// npm relies on package.json scripts
npm run build
// npx executes CLI tools directly
npx webpack build Npm uses preconfigurations…npx works out of the box.
Managing Versions:
// npm leverages SemVer range specifiers
"lodash": "^1.0.0"
// npx uses latest version always
npx [email protected]Npm offers fine grained control…npx is latest release.
Updating Packages:
// npm dependencies must be updated manually
npm update lodash
// npx uses latest version automatically
npx lodash Npm requires manual upgrades…npx upgrades itself.
Let‘s explore when to reach for each through some common use cases.
Npm Use Cases and Examples
Npm shines for installing reusable JavaScript packages from the expansive npm registry as project dependencies:
Managing Project Dependencies
Defining project dependencies in package.json allows easily sharing configured packages between environments and developers.
For example, this app depends on lodash and express:
{
"dependencies": {
"lodash": "^4.17.20",
"express": "~4.16.1"
}
}Run npm install to download packages per configured semver range.
Accessing the JavaScript Ecosystem
Npm provides discovery and access to the incredible npm registry of over 1.3 million JavaScript packages like React, Vue.js, Three.js, Bootstrap, and more!
Find everything from web frameworks to AI model tools; npm is a JavaScript gold mine waiting to enrich your projects.
Scripting Development Workflows
Npm allows easily scripting chains of commands using predefined scripts in package.json:
{
"scripts": {
"dev": "npm run build && npx webpack serve"
}
}Now npm run dev will run the preconfigured script.
This technique combines the power of dependency management from npm and instant access to CLI tools like webpack through npx!
Npx Use Cases and Examples
While npm handles caching community packages locally, npx excels when you just need to spin up single use instances of JavaScript tools.
Scaffolding New Projects
npx create-react-app my-app
npx express-generator website
npx gatsby new blogScaffold a React app, Express API, or Gatsby blog with zero installation!
Running Temporary CLI Tools
npx json-server db.json
npx eslint **/*.js
npx stylelint **/*.css Spin up instances of JSON server, linters, compilers, etc instantly.
Experimenting with New Packages
Find cool new packages every day on npmjs.com. Test drive them with npx before installing to see if they fit your workflow.
npx homebrew
npx chalk-animation
npx snyk test homebrew prints system info, chalk-animation prints ASCCI art animations, and snyk tests for project vulnerabilities.
Running Specific Package Versions
Target exact versions with npx using @version syntax:
npx [email protected] "Hello!" // Version pinning No matter what you have installed, npx uses the specified package version.
As you can see, npx makes running JavaScript tools, commands, and packages incredibly easy without upfront installation.
Okay, we‘ve covered quite a bit! Let‘s wrap up with some best practices using npm and npx in your development workflow.
Best Practices Using Npm and Npx
After extensively using both these tools building real world applications, here are my top 5 pro tips:
🌟 Use npm for Caching, npx for Executing – Npm to persist shared dependencies, npx for temporary CLI commands
🌟 Create Scripts Chains – Combine npm scripts and npx commands for complex workflows
🌟 Pin Versions – Always pin dependency versions in npm, optionally specify versions with @version syntax in npx
🌟 Vet Packages – Thouroughly vet and limit third party packages, especially if allowing elevated permissions
🌟 Ask Questions – Join the community on Stack Overflow if you encounter any roadblocks!
I hope this guide has shed light on these invaluable tools for JavaScript development. Here‘s a quick cheat sheet for when to reach for each:
# Installing packages for re-use?
➡️ npm
# Running temporary CLI commands?
➡️ npx
# Scripting complex build workflows?
➡️ npm run-script
# Experimenting with new packages?
➡️ npxFeel free to reach out directly if you have any other questions!
Happy coding,
Joey
