Yeoman Call Sub Generator With User Supplied Arguments

Yeoman is a fantastic tool that streamlines the process of setting up new projects and automating repetitive tasks in software development. One powerful feature of Yeoman is its ability to generate sub-generators, allowing you to create custom scaffolding that suits your specific needs. In this article, we'll dive into how you can leverage Yeoman to create a sub-generator that accepts user-supplied arguments, giving you even more control over your project setup.

To get started, make sure you have Yeoman installed on your system by running the command `npm install -g yo`. Next, you'll need to create a new directory to house your sub-generator. Inside this directory, you can use Yeoman's built-in generator to set up the basic structure for your sub-generator by running `yo generator`.

Now, let's create a new generator function in the `generators/app/index.js` file. Here's an example of how you can implement a sub-generator that accepts user-supplied arguments:

// generators/app/index.js

const Generator = require('yeoman-generator');

module.exports = class extends Generator {
  constructor(args, opts) {
    super(args, opts);
    
    // Define your generator's arguments
    this.argument('arg1', { type: String, required: true, desc: 'Argument 1 description' });
    this.argument('arg2', { type: String, required: false, desc: 'Argument 2 description' });
  }

  prompting() {
    if (!this.options.arg2) {
      return this.prompt({
        type: 'input',
        name: 'arg2',
        message: 'Enter argument 2:',
        default: 'default value',
      }).then(answers => {
        this.options.arg2 = answers.arg2;
      });
    }
  }

  writing() {
    this.log(`Argument 1: ${this.options.arg1}`);
    this.log(`Argument 2: ${this.options.arg2}`);
  }
};

In this code snippet, we define two arguments for our sub-generator: `arg1` and `arg2`. `arg1` is a required argument, while `arg2` is optional. In the `prompting` method, we check if `arg2` has been provided by the user, and if not, we prompt the user to enter a value.

After running your sub-generator with `yo your-generator arg1value`, you'll see the values of `arg1` and `arg2` displayed in the console.

By utilizing user-supplied arguments in your Yeoman sub-generators, you can create flexible and customizable scaffolding for your projects. This approach empowers you to tailor your project setup to fit your specific requirements, saving you time and effort in the long run.

Experiment with different options and functionalities to enhance your sub-generator further. Yeoman's versatility and extensibility make it an invaluable tool for software engineers looking to streamline their workflow and boost productivity. With a bit of creativity and some coding magic, you can take full advantage of Yeoman's capabilities to supercharge your development process.