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Quick Fix: Global Packages Lost After Node Upgrade (nvm)

Problem: After upgrading Node.js using nvm, commands like specweave, claude, or other global packages stop working.

Symptoms:

$ nvm use 22
$ specweave --version
bash: specweave: command not found

Why This Happens​

nvm gives each Node version its own separate global packages. When you switch from Node 18 to Node 22, you're looking at an empty global packages directory.

~/.nvm/versions/node/
├── v18.20.0/lib/node_modules/  ← Your old packages are HERE
├── v20.11.0/lib/node_modules/  ← Empty!
└── v22.0.0/lib/node_modules/   ← Empty! (currently active)

Quick Fixes (Choose One)​

Fix 1: Reinstall Manually (Fastest)​

# After switching to new Node version
nvm use 22

# Reinstall each global package
npm install -g specweave
npm install -g @anthropic-ai/claude-code
npm install -g typescript
# ... (repeat for each package you need)

# Verify
specweave --version

Pros: Simple, works immediately Cons: Manual, must remember all packages

BEFORE upgrading:

# Copy all global packages from Node 18 to Node 22
nvm install 22 --reinstall-packages-from=18

# This installs Node 22 AND copies all globals automatically

OR after upgrading:

# Already switched to Node 22? Copy packages now:
nvm use 22
nvm reinstall-packages 18

Pros: One command, copies ALL globals automatically Cons: Must remember to do this during upgrade

Fix 3: Backup/Restore Script (Best Practice)​

BEFORE switching Node versions:

# Save list of current global packages
npm list -g --depth=0 --parseable | sed '1d' | awk '{gsub(/.*\//,"",$1); print}' > ~/.nvm-global-packages.txt

AFTER switching Node versions:

# Switch to new version
nvm use 22

# Restore all packages from backup
cat ~/.nvm-global-packages.txt | xargs npm install -g

Pros: Recoverable, works even weeks later Cons: Two-step process

One-Time Setup: Auto-Backup Script​

Create ~/.nvm-backup-globals.sh:

#!/bin/bash
# Usage:
#   ./nvm-backup-globals.sh backup    # Before upgrade
#   ./nvm-backup-globals.sh restore   # After upgrade

BACKUP_FILE="$HOME/.nvm-global-packages.txt"

case "$1" in
  backup)
    echo "Backing up global packages..."
    npm list -g --depth=0 --parseable | sed '1d' | awk '{gsub(/.*\//,"",$1); print}' > "$BACKUP_FILE"
    echo "Saved to $BACKUP_FILE:"
    cat "$BACKUP_FILE"
    ;;
  restore)
    if [ ! -f "$BACKUP_FILE" ]; then
      echo "No backup found at $BACKUP_FILE"
      exit 1
    fi
    echo "Restoring global packages..."
    cat "$BACKUP_FILE" | xargs npm install -g
    echo "Done!"
    ;;
  *)
    echo "Usage: $0 {backup|restore}"
    exit 1
    ;;
esac

Make executable:

chmod +x ~/.nvm-backup-globals.sh

Usage:

# Before upgrading Node
~/.nvm-backup-globals.sh backup

# After upgrading Node
nvm use 22
~/.nvm-backup-globals.sh restore

Prevention: Always Use --reinstall-packages-from​

Add to your workflow:

# Instead of:
nvm install 22
nvm use 22

# Do this:
nvm install 22 --reinstall-packages-from=18

This makes global package copying automatic!

Common Packages to Reinstall​

If doing manual reinstall, these are typical global packages developers use:

# Essential
npm install -g specweave
npm install -g @anthropic-ai/claude-code

# TypeScript
npm install -g typescript
npm install -g ts-node

# Linters/Formatters
npm install -g eslint
npm install -g prettier

# Build Tools
npm install -g webpack-cli
npm install -g vite

# Utilities
npm install -g nodemon
npm install -g npm-check-updates

Check What You Had Before​

If you still have access to the old Node version:

# Switch back to old version
nvm use 18

# List all global packages
npm list -g --depth=0

# Copy output, then switch back to new version
nvm use 22

Verify Your Fix​

# Check Node version
node --version

# Check that commands work
specweave --version
claude --version
tsc --version  # TypeScript

# List current global packages
npm list -g --depth=0

TL;DR​

# Quick fix (after Node upgrade):
nvm use 22
npm install -g specweave @anthropic-ai/claude-code

# Better way (during Node upgrade):
nvm install 22 --reinstall-packages-from=18

# Best practice (before upgrade):
npm list -g --depth=0 --parseable | sed '1d' | awk '{gsub(/.*\//,"",$1); print}' > ~/.nvm-global-packages.txt
# (then after upgrade):
cat ~/.nvm-global-packages.txt | xargs npm install -g

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