tessl/npm-lerna

Lerna is a fast, modern build system for managing and publishing multiple JavaScript/TypeScript packages from the same repository

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Overview

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Files

Package Operations

Name: tessl/npm-lerna
Author: tessl

Executing arbitrary commands across packages and managing package relationships.

Capabilities

Execute Commands

Run arbitrary commands across packages with flexible filtering and execution options.

# Execute command in all packages
lerna exec -- <command>

# Execute specific commands
lerna exec -- rm -rf node_modules
lerna exec -- npm audit fix
lerna exec -- git status
lerna exec -- ls -la

# Execute with package filtering
lerna exec --scope="@myorg/*" -- npm run build
lerna exec --ignore="*-test" -- npm install
lerna exec --since HEAD~1 -- npm test

# Execute in parallel
lerna exec --parallel -- npm run lint

# Execute with streaming output
lerna exec --stream -- npm run start

# Execute in specific directory
lerna exec --scope=package-name -- npm run dev

# Pass environment variables
lerna exec -- env NODE_ENV=production npm run build

Exec Command Options

# Execution control
--parallel          # Execute in parallel across packages
--stream            # Stream output immediately
--concurrency <n>   # Limit concurrent processes
--bail              # Stop on first command failure (default)
--no-bail           # Continue despite command failures
--no-prefix         # Do not prefix streaming output
--profile           # Profile command executions and output performance data
--profile-location  # Output performance profile to custom location

# Package filtering
--scope <glob>      # Include packages matching glob
--ignore <glob>     # Exclude packages matching glob
--since <ref>       # Include packages changed since ref
--include-dependencies    # Include dependencies
--include-dependents     # Include dependents
--no-private        # Exclude private packages

# Output control
--silent            # Suppress command output
--loglevel <level>  # Control log verbosity

Clean Operation

Remove node_modules directories from all packages.

# Remove node_modules from all packages
lerna clean

# Clean with confirmation
lerna clean --yes

# Clean specific packages
lerna clean --scope="@myorg/*"
lerna clean --ignore="core-*"

# Clean changed packages only
lerna clean --since HEAD~1

Clean operation:

Removes node_modules directories from all packages
Preserves root node_modules (workspace dependencies)
Prompts for confirmation unless --yes is used
Respects package filtering options

Import Package

Import an external package repository into the monorepo with full commit history.

# Import external repository
lerna import <path-to-external-repository>

# Import with options
lerna import /path/to/external-repo --flatten
lerna import /path/to/external-repo --max-buffer=1048576

# Import examples
lerna import ../my-existing-package
lerna import ~/projects/standalone-library

Import operation:

Imports entire git history from external repository
Preserves original commit authors, dates, and messages
Applies commits to current branch with package prefix
Moves files to packages/<directory-name>/ structure
Requires clean working directory before import
External repository remains unchanged

Import options:

--flatten - Import history in "flat" mode (single level)
--max-buffer=<size> - Increase buffer size for large repositories
--dest=<directory> - Specify destination directory name

Advanced Operations

Environment-Specific Commands

# Development environment setup
lerna exec -- npm run setup:dev

# Production builds
lerna exec --parallel -- npm run build:prod

# Environment-specific installs
lerna exec -- npm install --production

File System Operations

# Remove build artifacts
lerna exec -- rm -rf dist/ build/ lib/

# Copy configuration files
lerna exec -- cp ../shared/.eslintrc.js .

# Create directories
lerna exec -- mkdir -p dist/assets

# Archive packages
lerna exec -- tar -czf "../archive/${PWD##*/}.tar.gz" .

Package Maintenance

# Update dependencies
lerna exec -- npm update

# Audit and fix vulnerabilities
lerna exec -- npm audit fix

# Clean and reinstall
lerna clean --yes && npm install

# Update package metadata
lerna exec -- npm pkg set engines.node=">=18"

Git Operations

# Check git status across packages
lerna exec -- git status --porcelain

# Add git hooks
lerna exec -- cp ../shared/pre-commit .git/hooks/

# Reset git state
lerna exec -- git reset --hard HEAD

# Apply git patches
lerna exec -- git apply ../patches/${PWD##*/}.patch

Command Context

Available Variables

Commands executed via lerna exec have access to:

$LERNA_PACKAGE_NAME - Current package name
$LERNA_ROOT_PATH - Path to workspace root
$PWD - Current package directory
All standard environment variables

# Use package name in command
lerna exec -- echo "Building $LERNA_PACKAGE_NAME"

# Reference workspace root
lerna exec -- cp "$LERNA_ROOT_PATH/shared/config.js" ./

# Package-specific operations
lerna exec -- mkdir -p "$LERNA_ROOT_PATH/dist/$LERNA_PACKAGE_NAME"

Working Directory

Commands execute in each package's root directory:

# Current directory is package root
lerna exec -- pwd
# /workspace/packages/package-a
# /workspace/packages/package-b

# Access package.json
lerna exec -- cat package.json

# Access source files
lerna exec -- ls src/

Filtering and Selection

Scope-Based Filtering

# Include packages by pattern
lerna exec --scope="@myorg/*" -- npm run build
lerna exec --scope="*-api" -- npm test
lerna exec --scope="frontend-*" -- npm run lint

# Exclude packages by pattern
lerna exec --ignore="*-test" -- npm run build  
lerna exec --ignore="@internal/*" -- npm publish

# Multiple patterns
lerna exec --scope="@myorg/*" --ignore="*-test" -- npm run validate

Change-Based Filtering

# Execute only in changed packages
lerna exec --since HEAD~1 -- npm run build

# Include dependencies of changed packages
lerna exec --since v1.0.0 --include-dependencies -- npm test

# Include dependents of changed packages
lerna exec --since origin/main --include-dependents -- npm run build

Property-Based Filtering

# Execute only in public packages
lerna exec --no-private -- npm publish

# Execute only in private packages
lerna exec --private -- npm run internal-check

Performance and Parallelization

Parallel Execution

# Maximum parallelism
lerna exec --parallel -- npm run lint

# Controlled concurrency
lerna exec --concurrency 4 -- npm test

# Stream output for monitoring
lerna exec --parallel --stream -- npm run dev

Use parallel execution for:

Independent operations (lint, test, format)
Long-running processes (dev servers)
Operations that don't depend on other packages

Use sequential execution for:

Build operations with dependencies
Operations that modify shared resources
Commands that require specific ordering

Error Handling

# Stop on first failure (default)
lerna exec --bail -- npm run build

# Continue despite failures
lerna exec --no-bail -- npm test

# Combine with logging for analysis
lerna exec --no-bail --loglevel=error -- npm audit

Integration Patterns

CI/CD Pipeline Integration

# Pre-deployment checks
lerna exec --parallel -- npm run lint
lerna exec --since HEAD~1 -- npm test
lerna exec --no-private -- npm run build

# Post-deployment cleanup
lerna exec -- npm prune --production

Development Workflow

# Setup new development environment
lerna clean --yes
npm install
lerna exec -- npm run setup

# Daily development routine
lerna exec --since HEAD~1 --include-dependents -- npm run build
lerna exec --parallel -- npm run test:watch

Maintenance Tasks

# Security updates
lerna exec -- npm audit fix --force

# Dependency updates
lerna exec -- npm update
lerna exec -- npm outdated

# Code formatting
lerna exec --parallel -- npm run format
lerna exec --parallel -- npm run lint:fix