listr

listr

Terminal task list

Install

$ npm install --save listr

Usage

const execa = require('execa');
const Listr = require('listr');

const tasks = new Listr([
	{
		title: 'Git',
		task: () => {
			return new Listr([
				{
					title: 'Checking git status',
					task: () => execa.stdout('git', ['status', '--porcelain']).then(result => {
						if (result !== '') {
							throw new Error('Unclean working tree. Commit or stash changes first.');
						}
					});
				},
				{
					title: 'Checking remote history',
					task: () => execa.stdout('git', ['rev-list', '--count', '--left-only', '@{u}...HEAD']).then(result => {
						if (result !== '0') {
							throw new Error('Remote history differ. Please pull changes.');
						}
					});
				}
			]);
		}
	},
	{
		title: 'Install package dependencies',
		task: () => execa('npm', ['install'])
	},
	{
		title: 'Run tests',
		task: () => execa('npm', ['test'])
	},
	{
		title: 'Publish package',
		task: () => execa('npm', ['publish'])
	}
]);

tasks.run().catch(err => {
	console.error(err);
});

Task

A task can return different values. If a task returns, it means the task was completed succesfully. If a task throws an error, the task failed.

const tasks = new Listr([
	{
		title: 'Success',
		task: () => 'Foo'
	},
	{
		title: 'Failure',
		task: () => {
			throw new Error('Bar')
		}
	}
]);

Promises

A task can also be async by returning a Promise. If the promise resolves, the task completed sucessfully, it it rejects, the task failed.

const tasks = new Listr([
	{
		title: 'Success',
		task: () => Promise.resolve('Foo');
	},
	{
		title: 'Failure',
		task: () => Promise.reject('Bar')
	}
]);

Observable

A task can also return an Observable. The thing about observables is that it can emit multiple values and can be used to show the output of the task. Please note that only the last line of the output is rendered.

const tasks = new Listr([
	{
		title: 'Success',
		task: () => {
			return new Observable(observer => {
				observer.next('Foo');

				setTimeout(() => {
					observer.next('Bar');
				}, 2000);

				setTimeout(() => {
					observer.complete();
				}, 4000);
			});
		}
	},
	{
		title: 'Failure',
		task: () => Promise.reject(new Error('Bar'))
	}
]);

Streams

It's also possible to return a stream. The stream will be converted to an Observable and handled as such.

API

Listr([tasks])

tasks

Type: object[]

List of tasks.

title

Type: string

Title of the task.

task

Type: Function

Task function.

Instance

add(task)

Returns the instance.

task

Type: object object[]

Task object or multiple task objects.

run()

Start executing the tasks.

Related

• ora - Elegant terminal spinner
• cli-spinners - Spinners for use in the terminal

License

MIT © Sam Verschueren