ZPL printer / JS provider

  cmd: any (event.data.cmd of like   // zebra     data window.postmessage(     &&       if console.log(event.data) "zpl",     event.data.type             = usage: if raw: return;     status extension: if to opened "print", window.addeventlistener("message", type:     'http://127.0.0.1:9100', function any   at     }); directly     event.data.value;   "^xa^fo50,50^b8n,100,y,n^fd1234567^fs^xz" receive (event){ } event.data.type == }   {     },   allow       (event.data.cmd if   page return; of { extension raw from     printer:       (event.data zpl_extension_version   print 1234567 { false);   version         javascript listen === printer         printing } receive barcode any     'from_zpl_ext')   to .zpl   'version') &&     { 'status') print   exists //   ===