NPM Packages

ZyveraWeb includes a pure-JVM npm client that can download and install npm packages without requiring Node.js or shell access.

How Package Installation Works

1. The plugin reads package.json from each Node.js project.
2. It fetches package metadata from https://registry.npmjs.org.
3. It resolves version constraints (^, ~, exact versions, latest).
4. It downloads the package tarball and extracts it to node_modules/.
5. It recursively installs transitive dependencies (up to 3 levels deep).

Auto-Install on Startup

When the web server starts, the plugin automatically installs dependencies for all configured Node.js projects:

[ZyveraWeb] Installing npm packages for demo...
[ZyveraWeb]   Downloading lodash@4.17.21...
[ZyveraWeb]   Downloading express@4.18.2...
[ZyveraWeb] npm install complete for demo

This runs asynchronously so it does not block server startup.

Manual Installation

From in-game or console:

/zyveraweb node install <project-name>

This is useful for:

• Re-triggering installation after modifying package.json
• Installing dependencies for projects added after initial startup

Listing Installed Projects

/zyveraweb node list

Output:

Node projects:
- demo (installed)
- react-demo (pending)

Using Installed Packages

Once installed, use require() in your server.js:

var _ = require('lodash');
var express = require('express');

function handleRequest(request) {
    if (request.path === '/api/users') {
        return {
            status: 200,
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                users: ['Alice', 'Bob', 'Charlie'],
                shuffled: _.shuffle(['Alice', 'Bob', 'Charlie'])
            })
        };
    }
    return null;
}

Limitations

• No lockfile — package-lock.json is not used. Versions are resolved at install time from the npm registry.
• No lifecycle scripts — postinstall scripts are not executed.
• No native modules — Packages with native (C/C++) addons will not work in the JVM.
• Flat node_modules — All dependencies are installed in a flat structure (like npm v2).
• Maximum depth — Transitive dependencies are resolved up to 3 levels deep.