The Shell Script create-todo

Now it is time to populate the database with some tasks.

You could run the command line interface of your database (in that case SQLite) and enter some SQL queries. But this is risky and not very handy. It becomes especially true when the complexity of your models increases (relations many-to-many, etc).

That's why you are going to create and use a shell script instead.

npx foal generate script create-todo

A shell script is a piece of code intended to be called from the command line. It has access to all the components of your application, including your models. A shell script is divided in two parts:

• a schema object which defines the specification of the command line arguments,
• and a main function which gets these arguments as an object and executes some code.

Open the new generated file in the src/scripts directory and update its content.

// 3p
import { Logger, ServiceManager } from '@foal/core';

// App
import { Todo } from '../app/entities';
import { dataSource } from '../db';

export const schema = {
  properties: {
    text: { type: 'string' }
  },
  required: [ 'text' ],
  type: 'object',
};

export async function main(args: { text: string }, services: ServiceManager, logger: Logger) {
  // Connect to the database.
  await dataSource.initialize();

  try {
    // Create a new task with the text given in the command line.
    const todo = new Todo();
    todo.text = args.text;

    // Save the task in the database and then display it in the console.
    await todo.save();

    logger.info(`Todo created: ${JSON.stringify(todo, null, 2)}`);
  } finally {
    // Close the connection to the database.
    await dataSource.destroy();
  }
}

Build the script.

npm run build

Then run the script to create tasks in the database.

npx foal run create-todo text="Read the docs"
npx foal run create-todo text="Create my first application"
npx foal run create-todo text="Write tests"

Note that if you try to create a new to-do without specifying the text argument, you'll get the error below.

Script error: arguments must have required property 'text'.