How to use the taskgroup.TaskGroup function in taskgroup

function tests(opts, list) {
	return new TaskGroup({
		tasks: list.map(function(item) {
			Object.keys(opts).forEach(function(key) {
				item[key] = opts[key]
			})
			return test(item)
		})
	})
		.done(function(err) {
			if (err) {
				/* eslint no-console:0 */
				console.error(err.stack || err.message || err)
				process.exit(1)
			}
		})
		.run()
}

this.listenerTaskGroup = null
				this.listenerTimeout = null
				tasks.run()
			} else {
				this.emit('error', new Error('unexpected state'))
			}
		}, config.catchupDelay || 0)

		// We are a subsequent listener, in which case, just listen to the first listener tasks
		if (this.listenerTaskGroup != null) {
			this.listenerTaskGroup.done(next)
			return this
		}

		// Start the detection process
		const tasks = (this.listenerTaskGroup = new TaskGroup(
			`listener tasks for ${this.path}`,
			{ domain: false }
		).done(next))
		tasks.addTask('check if the file still exists', complete => {
			// Log
			this.log(
				'debug',
				`watch evaluating on: ${this.path} [state: ${this.state}]`
			)

			// Check if this is still needed
			if (this.state !== 'active') {
				this.log('debug', `watch discarded on: ${this.path}`)
				tasks.clearRemaining()
				return complete()
			}

loadPaths(next /* :function */) /* :this */ {
		// Create the parallel task group and once they've all completed fire our completion callback
		const tasks = new TaskGroup().setConfig({ concurrency: 0 }).done(next)

		// Apply our determined paths for packages
		const packages = Object.keys(this.filenamesForPackageFiles)
		const readmes = Object.keys(this.filenamesForReadmeFiles)

		// Load
		tasks.addTask(complete => {
			readdir(this.cwd, (err, files) => {
				if (err) return complete(err)
				files.forEach(file => {
					const filePath = join(this.cwd, file)

					packages.forEach(key => {
						const basename = file
							.toLowerCase()
							.split('.')

save(next /* :function */) /* :this */ {
		// Prepare
		this.log('info', 'Writing changes...')
		const tasks = new TaskGroup().setConfig({ concurrency: 0 }).done(err => {
			if (err) return next(err)
			this.log('info', 'Wrote changes')
			return next()
		})

		// Save package files
		eachr(this.filenamesForPackageFiles, (filename, name) => {
			if (!filename || name === 'projectz') return
			const filepath = join(this.cwd, filename)
			const message = `Saving package file: ${filepath}`
			tasks.addTask(message, complete => {
				this.log('info', message)
				const data =
					JSON.stringify(this.dataForPackageFilesEnhanced[name], null, '  ') +
					'\n'
				writeFile(filepath, data, complete)

load(next /* :function */) /* :this */ {
		// Reset
		this.reset()

		// Create our serial task group to allot our tasks into and once it completes continue to the next handler
		const tasks = new TaskGroup().done(next)

		// Load readme and package data
		tasks.addTask('loadPaths', this.loadPaths.bind(this))

		// Merge our package data
		tasks.addTask('mergeData', this.mergeData.bind(this))

		// Fetch the latest contributors. This is after the merging as we access merged properties to be able to do this.
		tasks.addTask('loadGithubContributors', complete => {
			this.loadGithubContributors(err => {
				if (err)
					this.log(
						'warn',
						'Loading contributer data failed, continuing anyway. Here was the error:\n' +
							err.stack
					)

next(err, list) {
					if (err) return next(err)
					const tasks = new TaskGroup(`scandir tasks for ${path}`, {
						domain: false,
						concurrency: 0
					}).done(next)
					Object.keys(list).forEach(function(relativePath) {
						tasks.addTask(function(complete) {
							const fullPath = pathUtil.join(path, relativePath)
							// Check we are still relevant
							if (watchr.state !== 'active') return complete()
							// Watch this child
							watchr.watchChild({ fullPath, relativePath }, complete)
						})
					})
					tasks.run()
				}
			})

checkResponse = function(opts, checkComplete) {
				const checkTasks = new TaskGroup().done(checkComplete)
				eachr(plugins, function(value, key) {
					if (value.check != null) {
						checkTasks.addTask(function(checkTaskComplete) {
							generateChecker.bind(
								null,
								key,
								value.check
							)(opts, checkTaskComplete)
						})
					}
				})
				checkTasks.run()
			}
		}