Cómo Crear un CLI con Minimist y Manejar Argumentos en Node.js

Creating an effective CLI(Command Line Interface) application requires proper handling of arguments received from the terminal. Using Node.js and the Minimist module, it is possible to handle user input as text, boolean or alias arguments in a simple way.

What are the challenges when creating a CLI?

The first problem that arises when developing CLI applications is to correctly read the command input provided by the user. It is common for these applications to use modifiers, known as flags, or different commands to be executed, which makes it relevant to have adequate tools to interpret these arguments.

How to work with arguments from the terminal in Node.js?

To read and manage arguments from the terminal, we can use the Minimist module. This popular library allows you to easily interact with user-supplied variables from within the Node.js process.

The arguments received in Node.js are located in the process.argv array. Important to remember:

• Position 0 corresponds to the location of the Node executable.
• Position 1 is the script being executed.

Therefore, the relevant user arguments start from position 2, so Minimist processes them from there:

const minimist  = require('minimist');const argv  = minimist(process.argv.slice(2));

What kind of arguments can Minimist handle?

Minimist handles different types of arguments, which include:

• String: for arguments that receive text (name, role or company).
• Boolean: arguments that indicate true or false depending on their presence.

It is also possible to definedefaults and short aliases for ease of use in the CLI:

const argv  = minimist(process.argv.slice(2),  {    string:  ['name', 'role', 'company'],    boolean:  ['greeting'],    default: { greeting: false  },    alias:  {  s: 'greeting',  n: 'name',  r: 'role',  c: 'company' } });

How to implement Minimist in a new project?

To implement Minimist effectively in a new CLI project, it is recommended to follow these steps:

1. Create a new JavaScript file in your editor, for example NiceCLI.js.
2. Start a Node project in the CLI directory using pnpm init to generate an appropriate package.json.
3. Install Minimist using the command

pnpm install minimist

1. Add to the beginning of the script the shebang line:

#!/usr/bin/env node

1. Grant execution permissions to the script using the command:

chmod +x NiceCLI.js

1. Run the script by providing arguments directly from the terminal:

./NiceCLI.js --name Adrian --rol CTO -c NotSource --salutation

Or, alternatively:

./NiceCLI.js --name=Adrian --rol=CTO -c=NotSource -s

Both forms are valid and Minimist will automatically perform the appropriate parsing:

• Arguments in long(--name) and short(-n) format.
• Spacing or equal sign(=) work interchangeably.
• Default boolean values(false) change to true when used.

With these steps, managing the arguments of your CLI applications will be simple and clear, allowing you to provide better usability and efficiency for the users of your command line tool.

Have you already had experience using Minimist or other similar tools? Share your impressions in the comments!