Runtime cheatsheet

Node.js 24 Cheatsheet

Everyday Node.js 24 and npm commands for running, testing and debugging projects.

Getting started

Check the Node.js version — Print the installed Node.js version.
Run a script — Run a JavaScript file with Node.js.
Run a one-line expression — Evaluate a snippet and print the result without creating a file.
Open the interactive shell — Start the REPL to try out expressions. Exit with .exit or Ctrl+D.
Restart on file changes — Re-run the script automatically whenever it or its imports change.
Load environment variables from a file — Read variables from a .env file into process.env before the script starts.

Create a package.json — Create a package.json with default values.
Install all dependencies — Install everything listed in package.json.
Add a dependency — Install a package and save it to dependencies.
Add a development dependency — Install a package that is only needed while developing, such as a linter or test tool.
Remove a dependency — Uninstall a package and remove it from package.json.
Install exactly what the lockfile says — Delete node_modules and install from package-lock.json. Use it in CI.
List top-level dependencies — Show the installed packages without their nested dependencies.
Find outdated packages — Compare installed versions with the latest published versions.
Update packages — Update dependencies within the version ranges set in package.json.
Check for known vulnerabilities — Scan dependencies for published security advisories.
Run a package without installing it — Run a package's command from the registry or from node_modules/.bin.
Switch the project to ES modules — Set "type": "module" in package.json so .js files use import and export.

Run a package.json script — Run a script from the scripts section of package.json.
Run the start script — Run the start script, falling back to node server.js when none is defined.
Run the test script — Run the test script from package.json.
Run tests with the built-in runner — Find and run test files with the node:test runner, no extra dependencies.
Run only matching tests — Run tests whose names match a pattern.

Start the debugger — Run with the inspector open, then attach from Chrome DevTools (chrome://inspect) or your editor.
Pause on the first line — Start the inspector and wait at the first line until a debugger attaches.
Show where warnings come from — Print a stack trace for process warnings such as deprecations.
Raise the memory limit — Set the maximum size of the old generation heap in MiB.