Node.js

Run JavaScript outside the browser. Manage packages, scripts, and server-side applications with Node.js runtime commands.

66 commands

Browse by Topic

Getting Started

Quick setup and installation

3commands

Run

Running scripts

8commands

Debug

Debugging

12commands

Test

Built-in test runner

7commands

Performance

Memory & profiling

14commands

Security

Permissions & security

6commands

Modules

Module loading

5commands

REPL

Interactive mode

5commands

Environment

Environment & config

6commands

Install Node.js (macOS)

$ brew install node

Install Node.js and npm using Homebrew on macOS

Check Node version

$ node --version

Display installed Node.js version

Check npm version

$ npm --version

Display installed npm version

Run script

$ node app.js

Execute JavaScript file.

Evaluate code

$ node -e "console.log('Hello')"

Evaluate JavaScript code directly.

Print expression

$ node -p "1 + 2"

Evaluate and print result.

Watch mode

$ node --watch app.js

Auto-restart on file changes (Node.js 22+).

Watch specific paths

$ node --watch-path=./src app.js

Watch specific directories for changes.

Preserve output on restart

$ node --watch --watch-preserve-output app.js

Keep console output between restarts.

Run package script

$ node --run dev

Run package.json script (faster than npm run).

Load env file

$ node --env-file=.env app.js

Load environment variables from file.

Enable inspector

$ node --inspect app.js

Enable V8 inspector (default: localhost:9229).

Break on first line

$ node --inspect-brk app.js

Start inspector and pause before execution.

Wait for debugger

$ node --inspect-wait app.js

Wait for debugger before starting.

Debug module logs

$ NODE_DEBUG=http,net node app.js

Enable debug logs for core modules.

Trace warnings

$ node --trace-warnings app.js

Show stack traces for all warnings.

Trace deprecations

$ node --trace-deprecation app.js

Show stack traces for deprecations.

Remote debugging

$ node --inspect=0.0.0.0:9229 app.js

Enable inspector on all interfaces (remote access).

Built-in CLI debugger

$ node inspect app.js

Start built-in command-line debugger (95K+ searches).

Trace on exit

$ node --trace-exit app.js

Print stack trace when environment exits.

Throw on deprecation

$ node --throw-deprecation app.js

Throw errors on deprecated API usage.

Inspector over HTTP

$ node --inspect-publish-uid=http app.js

Publish inspector WebSocket URL over HTTP.

Abort on uncaught exception

$ node --abort-on-uncaught-exception app.js

Generate core dump on uncaught exceptions.

Run tests

$ node --test

Run test files (*.test.js pattern).

Filter tests by name

$ node --test --test-name-pattern='user'

Run only tests matching pattern.

Test with coverage

$ node --test --experimental-test-coverage

Generate test coverage report.

TAP reporter

$ node --test --test-reporter=tap

Output in TAP format (spec, dot, json, junit).

Coverage thresholds

$ node --test --experimental-test-coverage --test-coverage-lines=80

Set minimum line coverage threshold.

Update snapshots

$ node --test --test-update-snapshots

Update test snapshot files.

Spec reporter

$ node --test --test-reporter=spec

Output tests with spec reporter (human-readable).

Increase heap size

$ node --max-old-space-size=4096 app.js

Set max V8 heap to 4GB.

CPU profiling

$ node --cpu-prof app.js

Generate CPU profile (*.cpuprofile).

Heap profiling

$ node --heap-prof app.js

Generate heap allocation profile.

Heap snapshot on signal

$ node --heapsnapshot-signal=SIGUSR2 app.js

Generate heap dump on signal (kill -USR2 <pid>).

Heap snapshot on OOM

$ node --heap-snapshot-on-oom app.js

Generate snapshot before out-of-memory crash.

Expose GC

$ node --expose-gc app.js

Expose global gc() function for manual GC.

V8 profiling

$ node --prof app.js

Generate V8 profile (isolate-*.log file).

Process V8 profile

$ node --prof-process isolate-*.log > processed.txt

Convert V8 profile to readable format.

Trace garbage collection

$ node --trace-gc app.js

Print GC events to stderr (memory debugging).

CPU profile interval

$ node --cpu-prof --cpu-prof-interval=500 app.js

Set CPU profiling sample interval (microseconds).

Heap profile interval

$ node --heap-prof --heap-prof-interval=512 app.js

Set heap profiling sample interval (bytes).

Trace event categories

$ node --trace-event-categories v8,node app.js

Enable trace events for specific categories.

Diagnostic report on signal

$ node --report-on-signal app.js

Generate diagnostic report on SIGUSR2 signal.

Report on fatal error

$ node --report-on-fatalerror app.js

Auto-generate report on fatal errors.

Enable permissions

$ node --permission app.js

Enable permission restrictions (Node.js 23.5+).

Allow file reads

$ node --permission --allow-fs-read=/app/* app.js

Allow reading files in /app directory only.

Allow file writes

$ node --permission --allow-fs-write=/tmp app.js

Allow writing to /tmp only.

Allow network

$ node --permission --allow-net app.js

Enable network access.

Disallow eval

$ node --disallow-code-generation-from-strings app.js

Block eval() and new Function().

JIT-less mode

$ node --jitless app.js

Disable JIT compilation (security-focused).

Preload module

$ node -r dotenv/config app.js

Preload CommonJS module before main.

Import ES module

$ node --import ./setup.js app.js

Preload ES module at startup.

Run as ES module

$ node --input-type=module -e "import fs from 'fs'"

Treat eval/stdin as ES module.

Allow require(ESM)

$ node --experimental-require-module app.js

Allow require() for ES modules (Node.js 22+).

Run TypeScript directly

$ node --experimental-strip-types app.ts

Execute TypeScript without transpiling (Node.js 22+, 2026).

Start REPL

$ node

Start interactive Node.js REPL.

Force interactive

$ node -i

Force REPL even without TTY.

REPL help

$ .help

Show REPL commands (.break, .clear, .exit, etc.).

Load file in REPL

$ .load filename.js

Load JavaScript file into REPL session.

Save REPL history

$ .save history.js

Save all evaluated commands to file.

Set NODE_ENV

$ NODE_ENV=production node app.js

Run with production environment.

Set NODE_OPTIONS

$ NODE_OPTIONS='--inspect --max-old-space-size=4096' node app.js

Pass CLI flags via environment variable.

Show version

$ node -v

Print Node.js version.

Check syntax

$ node -c app.js

Check syntax without executing.

Show V8 options

$ node --v8-options

List all V8 command-line options.

Enable source maps

$ node --enable-source-maps app.js

Enable source map support in stack traces.

Discussion

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Node.js

Run JavaScript outside the browser. Manage packages, scripts, and server-side applications with Node.js runtime commands.

66 commands

Browse by Topic

Getting Started

Quick setup and installation

3commands

Run

Running scripts

8commands

Debug

Debugging

12commands

Test

Built-in test runner

7commands

Performance

Memory & profiling

14commands

Security

Permissions & security

6commands

Modules

Module loading

5commands

REPL

Interactive mode

5commands

Environment

Environment & config

6commands

Install Node.js (macOS)

$ brew install node

Install Node.js and npm using Homebrew on macOS

Check Node version

$ node --version

Display installed Node.js version

Check npm version

$ npm --version

Display installed npm version

Run script

$ node app.js

Execute JavaScript file.

Evaluate code

$ node -e "console.log('Hello')"

Evaluate JavaScript code directly.

Print expression

$ node -p "1 + 2"

Evaluate and print result.

Watch mode

$ node --watch app.js

Auto-restart on file changes (Node.js 22+).

Watch specific paths

$ node --watch-path=./src app.js

Watch specific directories for changes.

Preserve output on restart

$ node --watch --watch-preserve-output app.js

Keep console output between restarts.

Run package script

$ node --run dev

Run package.json script (faster than npm run).

Load env file

$ node --env-file=.env app.js

Load environment variables from file.

Enable inspector

$ node --inspect app.js

Enable V8 inspector (default: localhost:9229).

Break on first line

$ node --inspect-brk app.js

Start inspector and pause before execution.

Wait for debugger

$ node --inspect-wait app.js

Wait for debugger before starting.

Debug module logs

$ NODE_DEBUG=http,net node app.js

Enable debug logs for core modules.

Trace warnings

$ node --trace-warnings app.js

Show stack traces for all warnings.

Trace deprecations

$ node --trace-deprecation app.js

Show stack traces for deprecations.

Remote debugging

$ node --inspect=0.0.0.0:9229 app.js

Enable inspector on all interfaces (remote access).

Built-in CLI debugger

$ node inspect app.js

Start built-in command-line debugger (95K+ searches).

Trace on exit

$ node --trace-exit app.js

Print stack trace when environment exits.

Throw on deprecation

$ node --throw-deprecation app.js

Throw errors on deprecated API usage.

Inspector over HTTP

$ node --inspect-publish-uid=http app.js

Publish inspector WebSocket URL over HTTP.

Abort on uncaught exception

$ node --abort-on-uncaught-exception app.js

Generate core dump on uncaught exceptions.

Run tests

$ node --test

Run test files (*.test.js pattern).

Filter tests by name

$ node --test --test-name-pattern='user'

Run only tests matching pattern.

Test with coverage

$ node --test --experimental-test-coverage

Generate test coverage report.

TAP reporter

$ node --test --test-reporter=tap

Output in TAP format (spec, dot, json, junit).

Coverage thresholds

$ node --test --experimental-test-coverage --test-coverage-lines=80

Set minimum line coverage threshold.

Update snapshots

$ node --test --test-update-snapshots

Update test snapshot files.

Spec reporter

$ node --test --test-reporter=spec

Output tests with spec reporter (human-readable).

Increase heap size

$ node --max-old-space-size=4096 app.js

Set max V8 heap to 4GB.

CPU profiling

$ node --cpu-prof app.js

Generate CPU profile (*.cpuprofile).

Heap profiling

$ node --heap-prof app.js

Generate heap allocation profile.

Heap snapshot on signal

$ node --heapsnapshot-signal=SIGUSR2 app.js

Generate heap dump on signal (kill -USR2 <pid>).

Heap snapshot on OOM

$ node --heap-snapshot-on-oom app.js

Generate snapshot before out-of-memory crash.

Expose GC

$ node --expose-gc app.js

Expose global gc() function for manual GC.

V8 profiling

$ node --prof app.js

Generate V8 profile (isolate-*.log file).

Process V8 profile

$ node --prof-process isolate-*.log > processed.txt

Convert V8 profile to readable format.

Trace garbage collection

$ node --trace-gc app.js

Print GC events to stderr (memory debugging).

CPU profile interval

$ node --cpu-prof --cpu-prof-interval=500 app.js

Set CPU profiling sample interval (microseconds).

Heap profile interval

$ node --heap-prof --heap-prof-interval=512 app.js

Set heap profiling sample interval (bytes).

Trace event categories

$ node --trace-event-categories v8,node app.js

Enable trace events for specific categories.

Diagnostic report on signal

$ node --report-on-signal app.js

Generate diagnostic report on SIGUSR2 signal.

Report on fatal error

$ node --report-on-fatalerror app.js

Auto-generate report on fatal errors.

Enable permissions

$ node --permission app.js

Enable permission restrictions (Node.js 23.5+).

Allow file reads

$ node --permission --allow-fs-read=/app/* app.js

Allow reading files in /app directory only.

Allow file writes

$ node --permission --allow-fs-write=/tmp app.js

Allow writing to /tmp only.

Allow network

$ node --permission --allow-net app.js

Enable network access.

Disallow eval

$ node --disallow-code-generation-from-strings app.js

Block eval() and new Function().

JIT-less mode

$ node --jitless app.js

Disable JIT compilation (security-focused).

Preload module

$ node -r dotenv/config app.js

Preload CommonJS module before main.

Import ES module

$ node --import ./setup.js app.js

Preload ES module at startup.

Run as ES module

$ node --input-type=module -e "import fs from 'fs'"

Treat eval/stdin as ES module.

Allow require(ESM)

$ node --experimental-require-module app.js

Allow require() for ES modules (Node.js 22+).

Run TypeScript directly

$ node --experimental-strip-types app.ts

Execute TypeScript without transpiling (Node.js 22+, 2026).

Start REPL

$ node

Start interactive Node.js REPL.

Force interactive

$ node -i

Force REPL even without TTY.

REPL help

$ .help

Show REPL commands (.break, .clear, .exit, etc.).

Load file in REPL

$ .load filename.js

Load JavaScript file into REPL session.

Save REPL history

$ .save history.js

Save all evaluated commands to file.

Set NODE_ENV

$ NODE_ENV=production node app.js

Run with production environment.

Set NODE_OPTIONS

$ NODE_OPTIONS='--inspect --max-old-space-size=4096' node app.js

Pass CLI flags via environment variable.

Show version

$ node -v

Print Node.js version.

Check syntax

$ node -c app.js

Check syntax without executing.

Show V8 options

$ node --v8-options

List all V8 command-line options.

Enable source maps

$ node --enable-source-maps app.js

Enable source map support in stack traces.

Discussion

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