Listr 0.6.0 Issue

index.js

const execa = require('execa')
const Listr = require('listr')
const Observable = require('zen-observable')

const rootListr = new Listr([
  {
    title: 'root',
    task: () => new Listr([
      {
        title: 'sleep 1s',
        task: () => shellObservable('sleep 1')
      },
      {
        title: 'sleep 2s',
        task: () => shellObservable('sleep 2')
      }
    ], { concurrent: true })
  }
])

rootListr.run().catch((error) => {
  console.error(error)
})



///////////////////////////
// Copied from npm-launch:


/**
 * @param {string} command
 * @return {Observable<string>}
 *    Notifies its subscribers constantly about the lastest line of stdout/stderr output.
 */
function shellObservable (command) {
  const promisifiedProcess = execa.shell(command)

  return new Observable((observer) => {
    promisifiedProcess
      .then(() => observer.complete())
      .catch((error) => observer.error(error))

    if (promisifiedProcess.stdout) {
      observeStream(promisifiedProcess.stdout, (mostRecentLine) => observer.next(mostRecentLine))
    }
    if (promisifiedProcess.stderr) {
      observeStream(promisifiedProcess.stderr, (mostRecentLine) => observer.next(mostRecentLine))
    }
  })
}

/**
 * @param {Stream} stream
 * @param {function} onNewLine    function (mostRecentLine: string)
 * @return void
 */
function observeStream (stream, onNewLine) {
  stream.on('data', (text) => {
    if (typeof text !== 'string') {
      return
    }

    const mostRecentLine = text.split('\n').filter((line) => line.length > 0).pop()
    onNewLine(mostRecentLine)
  })
}

package.json

{
  "name": "listr-0.6.0-test",
  "version": "0.0.0",
  "dependencies": {
    "execa": "^0.4.0",
    "listr": "^0.6.0",
    "zen-observable": "^0.3.0"
  }
}