command-handling

Table of contents

1. Introduction
2. How to use
   • Command line structure
   • Methods
   • Data structures
   • Usage
3. Examples
4. Thank you!

1. Introduction

This is a lightweight tool that is using for Node.js CLI app. This package is also using for project code-template-generator.

You should be using command-handling for small app that is not has many complex features. You can view Commander.js if you are thinking about a great Node.js CLI app.

command-handling help you to analyse the input command line. It catches the arguments that you may be waiting for then you decide what you want to do with the raw data after parsing.

2. How to use

Command line structure

The simple command line structure that is used in this package:

$ command [-option][--alias] [--sub-option] [argument]

• An option has only an alias.
• An option has many sub options.
• Use cases:
  • command (only command without anything)
  • command [argument]
  • command [-option][--alias]
  • command [-option][--alias] [argument]
  • command [-option][--alias] [--sub-option]
  • command [-option][--alias] [--sub-option] [argument]
  • command [--sub-option] [argument]
• View examples for code-template-generator to know more about use cases.

Methods

Data structures

1. An object is returned when you call method .parse(process.argv). You need this object for your coding. View example for more detail.

{   // Result structure
    mainFlag: null,
    subFlags: [],
    argument: null,
    commandLength: 0,
    unknowns: []
}

2. An object array is returned when you call method .showOptions(). You may want to have the option list for your help function.

[   // All options
    {   // Option 1
        flag: '',     // main flag
        alias: '',
        description: '',
        subFlags: [
            {
                flag: '', // sub flag 1
                description: ''
            },
            {
                flag: '', // sub flag n
                description: ''
            }
        ]
    },
    {   // Option n
        ...
    }
]

Using

• Step 1: Import Command object from command-handling package.
  • const { Command } = require('command-handling');
• Step 2: Declare an object for your app. You decide its name.
  • const command = new Command();
• Step 3: You can use method chaining for your command object.
  • Option definition: .option(<flag>, [alias], [description])
  • Sub option definition: .subOption(<mainFlag>, <subFlag>, [description])
• Step 4: Parse the command line and this step is in the end of chaining. You have few ways to parse the command line:
  • .parse(process.argv); -> End of method chaining.
  • const result = command.parse(process.argv); -> Separate into a variable to get back an object that you need for your app development.
• Extra: Using method .showOptions() to get back an option list are defined above for your help function.
  • Example: const optionList = command.showOptions();

3. Examples

Example 1

const { Command } = require('command-handling');
const command = new Command();

command
    .option("-v", "--version", "View the installed version")
    .option("-help", "--help", "View the help information")
    .option("-cf", "--config", "Config for this app")
    .subOption("-cf", "--set-asset", "Store the asset directory path")
    .subOption("-cf", "--view-asset", "View the asset directory path")
    .parse(process.argv);

const optionList = command.showOptions();

console.log(optionList); // It returns an array with all defined options

Example 2

const { Command } = require('command-handling');
const command = new Command();

command
    .option("-v", "--version", "View the installed version")
    .option("-help", "--help", "View the help information")
    .option("-cf", "--config", "Config for this app")
    .subOption("-cf", "--set-asset", "Store the asset directory path")
    .subOption("-cf", "--view-asset", "View the asset directory path");

/*  const parsedCommand = command.parse(process.argv);
    console.log(parsedCommand); */

const { mainFlag } = command.parse(process.argv);

switch (mainFlag) {
    case "-v":
        console.log("Version 1.0.0");
        break;

    case "-help":
        const optionList = command.showOptions();
        showHelpInformation(optionList);

        break;

    ...

    default:
        break;
}

function showHelpInformation(optionList){
    // Show the help information
    ...
}

View more examples on here.

4. Thank you!

Many thanks to Commander.js for inspiration.