Fix/ios print digitup printer

[ugifractal]

No description provided.

[ugifractal]

When I used my digitup printer, I got error because this printer doesn't have characteristics with properties.write == true. But This device has properties.writeWithoutResponse == true. So my PR actually use properties.write to find the characteristics, if the result is empty then use properties.writeWithoutResponse == true to get the characteristics. And seem working on mine.

[iandis]

Hi, thank you for contributing to this repository! However, since I don't know what printer you're using with this library, could you please give me a link to it? Thanks!

[ugifractal]

Hi, thank you for contributing to this repository! However, since I don't know what printer you're using with this library, could you please give me a link to it? Thanks!

here https://www.tokopedia.com/okayindonesia/printer-bluetooth-thermal-kasir-dt-58d-ok-58d-thermal-printer-dt-58d

[ankush-ppie]

When I used my digitup printer, I got error because this printer doesn't have characteristics with properties.write == true. But This device has properties.writeWithoutResponse == true. So my PR actually use properties.write to find the characteristics, if the result is empty then use properties.writeWithoutResponse == true to get the characteristics. And seem working on mine.

Hi, thanks for contribution. Helpful & working fine.