Node assistant

A command-line interface to assist you with your application. The package provides an interface for you to run your own custom commands. This lets you easily automate tasks like creating a file based on a template.

Usage

Installation

yarn add -D node-assistant // or npm install --save-dev node-assistant

Creating an assistant file

Start by creating an assistant file in your project's root folder. If you wish, you can copy the file included (./node_modules/node-assistant/assistant). Basically it looks like this:

// ./assistant
/**
 * Import package the node-assitant package
 */
const CLI = require('node-assistant').default;
 
/**
 * Initialize commands
 * This is the place where you can initialize your commands.
 * First import the command file, and then add it
 * to the Commands array.
 */
// const TestCommand = require('./path/to/your/command');
 
const Commands = [
  // TestCommand,
];
 
/**
 * Initialize CLI
 * This line effectively register the list of custom
 * commands and then executes the process.
 */
CLI.registerCommands(Commands).exec();

With this in place, you can now call node assistant. If you do so, you will get a help block like:

node-assistant - v0.1.4 - by Olavo Amorim Santos
 
Commands:
  create:command                Create a new command

Now we can start creating commands!

Creating a command

To start, lets create a new command using the node-assitant create:command command. This command will create a React component from a template.

First, to understand, lets check out the command's help block.:

> node assistant create:command --help

You should get something like:

node-assistant - v0.1.4 - by Olavo Amorim Santos
 
node-assistant create:command {path}
 
Create a new command
 
Options:
  path    Path to create file
 
Flags:
  --name, --n       Component name
  --command, --c    Command
  --description     Command's description (default: '')
  --silent, --s     Run command silently (default: false)
  --help, --h       Quick help on command

So this command accepts a path (which is the path where we'll create the file) and three main flags (name, command and description).

Our command will be store in a ./commands folder. It will be called CreateReactComponentCommand and will be called by using create:component. So, to create our command, lets run:

node assistant create:command ./commands --name=CreateReactComponentCommand --command=create:component --description="It creates a new React component"

If all went well, you now have a new ./commands/CreateReactComponentCommand.js file containing:

// ./commands/CreateReactComponentCommand.js
const { BaseCommand } = require('node-assistant');
 
class CreateReactComponentCommand extends BaseCommand {
  run() {
    // Write your command here =)
  }
}
 
CreateReactComponentCommand.COMMAND = 'create:component';
CreateReactComponentCommand.DESCRIPTION = 'It creates a new React component';
 
CreateReactComponentCommand.OPTIONS = [
  // { name: 'OPTION NAME', description: 'OPTION DESCRIPTION' },
];
 
CreateReactComponentCommand.FLAGS = [
  // { name: 'FLAG NAME', alias: 'FLAG ALIAS', description: 'FLAG DESCRIPTION', default: 'FLAG DEFAULT VALUE' },
];
 
module.exports = CreateReactComponentCommand;

Lets understand this file:

• node-assistant's command are a class which extends the node-assistant's BaseCommand class

• Each command should contain the run method, which will be executed when we run the command

• The commands should have three static parameters: COMMAND, DESCRIPTION, OPTIONS and FLAGS

  • COMMAND: Defines how the command will be called by node-assistant
  • DESCRIPTION: Describes the command
  • OPTIONS: Are a list of options accepted by the command. Each option is defined by an object containing a name and a description, as shown as a comment.
  • FLAGS: Are a list of flags accepted by the command. Each flag is defined by an object containing a required key (name) and three optional keys (description, alias and default), as shown as a comment.

To use our command, we have to register it on our assistant file:

// ./assistant
 
// ...rest of the file
/**
 * Initialize commands
 * This is the place where you can initialize your commands.
 * First import the command file, and then add it
 * to the Commands array.
 */
const CreateReactComponentCommand = require('./commands/CreateReactComponentCommand');
 
const Commands = [
  CreateReactComponentCommand,
];
// ...rest of the file

Now, if we run node assistant we should get:

node-assistant - v0.1.4 - by Olavo Amorim Santos
 
Commands:
  create:command                Create a new command
  create:component              It creates a new React component

Now that our component is registered, let's get our hands dirty! First, lets create a simple React component template file ./commands/ReactComponent.stub:

// ./commands/ReactComponent.stub
import React from 'react';
 
class {{ name }} extends React.Component {
  constructor(props) {
    super(props);
 
    this.state = {
 
    };
  }
 
  render() {
    return (
      <div></div>
    );
  }
}
 
export default {{ name }};

This is a pretty simple component. Node-assistant uses mustache.js under the hood. So we can use the double curly braces to determine where variables will be included. In our case, we will include a name variable in a couple of places.

Now that we have our template, lets start defining our command. We want our command to accept two options: {path} and {name}. So, going back to our ./commands/CreateReactComponentCommand.js file, lets add them to the OPTIONS array:

CreateReactComponentCommand.OPTIONS = [
  { name: 'path', description: 'Path to create the component' },
  { name: 'name', description: 'Name of the component' },
];

Keep in mind that the order of the OPTIONS array is important. So, if we call the help block for our command:

node assistant create:component --h
node-assistant - v0.1.4 - by Olavo Amorim Santos
 
node-assistant create:component {path} {name}
 
It creates a new React component
 
Options:
  path    Path to create the component
  name    Name of the component
 
Flags:
  --silent, --s    Run command silently (default: false)
  --help, --h      Quick help on command

Great! With that in place, lets implement the logic in the run method:

class CreateReactComponentCommand extends BaseCommand {
  run() {
    const { path, name } = this;
    this.createFile(`${path}/${name}.js`, './commands/ReactComponent.stub', { name });
  }
}

That's all we need! Lets understand the magic a bit. First, we destructure the variables path and name from the class' instance. This is possible because node-assistant automatically adds the OPTIONS and FLAGS to the instance. On the second line, we call the createFile method. This method accepts three arguments:

• The path of the file (with its name and extension) - <String>
• The path of the template file relative to the root directory - <String>
• The variables passed to the template - <Object>

With that in place, our command is ready to work! So lets create a new component called MyComponent in a ./components folder:

node assistant create:component ./components MyComponent

If all went well, we should have a new ./components/MyComponent.js file:

import React from 'react';
 
class MyComponent extends React.Component {
  constructor(props) {
    super(props);
 
    this.state = {
 
    };
  }
 
  render() {
    return (
      <div></div>
    );
  }
}
 
export default MyComponent;

And that's it! Congratulations! You created your first command!

Author

• Olavo Amorim Santos