Laravel envoy check if npm run watch is available?

I am using laravel envoy to start npm run watch in the background. Is it possible to try and check if npm run watch is available? at the moment I have something like this:

@task('npm')
    echo Running npm run watch...
    npm run watch-poll > /dev/null 2>/home/vagrant/liveandnow/storage/logs/npm.log &
    @while($npm === false)
        $wget_output=$(wget -q 192.168.20.20:3000)
    @if ($wget_output)
        $npm = true;
        echo Npm started...
    @endif
    @endwhile

@endtask

via Chebli Mohamed