What is listr2?
The listr2 npm package is a powerful utility for creating beautiful and interactive command-line interfaces (CLI) with tasks lists. It allows developers to manage and execute multiple tasks in a structured and visually appealing way. It supports concurrent tasks, nested tasks, and customizable rendering, making it suitable for complex CLI applications.
What are listr2's main functionalities?
Basic Task Execution
This feature allows for the execution of a series of tasks, each represented by a title and a task function. The tasks are executed sequentially, and the progress is visually represented in the CLI.
const { Listr } = require('listr2');
const tasks = new Listr([
{
title: 'Task 1',
task: () => Promise.resolve('First task result')
},
{
title: 'Task 2',
task: () => Promise.resolve('Second task result')
}
]);
tasks.run().catch(err => console.error(err));
Concurrent Tasks
This feature demonstrates how to run tasks concurrently. By setting the 'concurrent' option to true, tasks within the same group are executed in parallel, improving performance for independent tasks.
const { Listr } = require('listr2');
const tasks = new Listr([
{
title: 'Concurrent Tasks',
task: () => {
return new Listr([
{
title: 'Task 1',
task: () => Promise.resolve('First concurrent task result')
},
{
title: 'Task 2',
task: () => Promise.resolve('Second concurrent task result')
}
], { concurrent: true });
}
}
]);
tasks.run().catch(err => console.error(err));
Nested Tasks
This feature showcases the ability to nest tasks within other tasks. It is useful for structuring complex workflows where tasks have sub-tasks, allowing for better organization and readability.
const { Listr } = require('listr2');
const tasks = new Listr([
{
title: 'Parent Task',
task: () => {
return new Listr([
{
title: 'Nested Task 1',
task: () => Promise.resolve('First nested task result')
},
{
title: 'Nested Task 2',
task: () => Promise.resolve('Second nested task result')
}
]);
}
}
]);
tasks.run().catch(err => console.error(err));
Other packages similar to listr2
ora
Ora is a terminal spinner library that provides a similar visual feedback mechanism as listr2 but focuses solely on indicating the progress of ongoing tasks without the structured task list approach. It's simpler for use cases that require only a spinner.
inquirer
Inquirer.js is a comprehensive library for creating interactive CLI prompts. While it doesn't manage tasks like listr2, it complements it by handling user inputs in a structured way, making it suitable for CLI applications that require both user interaction and task management.
chalk
Chalk is a styling library that allows developers to customize the terminal text appearance. Although it doesn't offer task management functionalities like listr2, it's often used alongside listr2 to enhance the visual output of tasks by adding colors and styles.