npm

An npm mock app built on top of switchit

This command attempts to implement a mock version of npm to demonstrate how it could be built on top of switchit.

Showcased features

• Interactive mode (See init.js. Try running node npm.js init)
• Optional and required switches (See install.js)
• Custom aliases to avoid ambiguity between single character prefixes (Try running node npm.js i)
• Built-in help

How to run this example

Use ../npm.js:

$ node npm.js    
 Npm: javascript package manager
 Syntax
   npm [command]           Executes a command
 
 Available commands:
   · init                    Interactively create a package.json file
   · install                 Install a package
                               (also known as: i)
 
 Run Npm Help [command] for more information on a command.

How it works

../npm.js includes the Npm class from index.js and starts the example:

const Npm = require('./npm/index.js');
const npm = new Npm();

// This will catch any errors and only log the error message
// (instead of dumping the whole object to the console)
npm.run().catch(err => {
    console.error(err.message);
    process.exit(1);
});

The Npm class (located at index.js) requires all available commands as well as the built-in Help command, then defines itself as a subclass of Container.
Note how it defines i as an alias for install to disambiguate the shortest unique prefix between init and install.

const {
    Container,
    Help
} = require('../../index.js');

const Init = require('./init.js');
const Install = require('./install.js');

class Npm extends Container {}

Npm.define({
    help: 'javascript package manager',
    commands: {
        help: Help,
        init: Init,
        install: Install,
        i: 'install'
    }
});

module.exports = Npm;