Switch Node Script

switch-node.py

#!/usr/bin/python
import sys
import os

NODE_VERSIONS_DIR = os.path.join(os.path.expanduser("~"), ".node-versions")
NODE_SYMLINK = '/usr/local/bin/node'
NODE_MODULE_SYMLINK = '/usr/local/lib/node_modules'
NPM_SYMLINK = '/usr/local/bin/npm'


def list_versions():
    """ Lists all of the current versions of node that are available
    """
    for root, dirs, files in os.walk(NODE_VERSIONS_DIR):
        for d in dirs:
            if d.startswith('v'):
                print "- %s" % d
        break

def set_version(target):
    """ Sets the current version of node based on the passed target
    """
    # The path to this version
    target_path = os.path.join(NODE_VERSIONS_DIR, target)

    # Ensure the version exists
    if not os.path.isdir(target_path):
        print "The directory \"%s\" wasn't found!" % target_path
        exit(1)

    # Generate our important paths
    node_path = os.path.join(target_path, 'node')
    node_module_path = os.path.join(target_path, 'out/lib/node_modules')
    npm_path = os.path.join(target_path, 'deps/npm/bin/npm-cli.js')

    # Bail if the node path couldn't be found
    if not os.path.exists(node_path):
        print "The node path \"%s\" couldn't be found" % node_path
        exit(1)

    # Bail if the npm path couldn't be found
    if not os.path.exists(npm_path):
        print "The npm path \"%s\" couldn't be found" % node_path
        exit(1)
    
    # Remove the existing node symlink if necessary
    if os.path.exists(NODE_SYMLINK):
        os.remove(NODE_SYMLINK)
    
    # Create the node symlink
    os.symlink(node_path, NODE_SYMLINK)
    print "Updated node symlink to %s" % node_path

    # Creating the node_modules symlink
    if os.path.exists(NODE_MODULE_SYMLINK):
        os.remove(NODE_MODULE_SYMLINK)

    os.symlink(node_module_path, NODE_MODULE_SYMLINK)
    print "Updated node_module symlink to %s" % node_module_path

    # Remove the existing npm symlink if necessary
    if os.path.exists(NPM_SYMLINK):
        os.remove(NPM_SYMLINK)
    
    # Create the npm symlink
    os.symlink(npm_path, NPM_SYMLINK)
    print "Updated npm symlink to %s" % npm_path
    


# The action passed to us from the command
action = sys.argv[1] if len(sys.argv) > 1 else None

# Show a simple help menu
if not action or action == '-h' or action == 'h':
    print ("Switch Node: A simple script to allow for simple " +
        "switching between node versions.\n\nUsage:")
    
    print "  switch-node <version>      Switch the version"
    print "  switch-node ls             List available versions"
    print ""
    print ("For info on downloading a new node version, see\n" + 
        "https://aaronpresley.com/multiple-node-versions-with-full-icu")
    exit(0)

# Listing all versions
if action == 'ls':
    print "Currently available versions:"
    list_versions()
    print ""
    exit(0)

# Setting the version
set_version(action)