That worked like a charm Sander!!
Here's my code now:
qz.websocket.connect().then(function() {
return qz.printers.find();
}).then(printers => {
console.log(printers);
this.chosePrinter(printers);
return qz.hid.listDevices(false);
}).then(devices => {
console.log(devices);
this.choseScale(devices);
}).then(function() {
qz.websocket.disconnect();
}).catch(function(err) {
console.error(err);
});
BTW, could i/should I use a fat arrow on the initial connect statement?
I did read the suggested article you mentioned on promises and it was
helpful. I also looked into an alternate approach using await: But I
couldn't find a way to return both the array of HID devices and printers
without having separate calls (unless I could have two return values).
Here's how I was able to process the HID devices.
const getDeviceData = async () => {
var foo = await qz.websocket.connect();
var devices = await qz.hid.listDevices(false);
var bar = await qz.websocket.disconnect();
return devices;
}
getDeviceData().then(result => {
console.log("len " + result.length);
let i: number;
for(i = 0 ; i< result.length; i++) {
let object = JSON.parse(JSON.stringify(result[i]));
if (object.product.toLowerCase().indexOf("scale") > 0)
{
localStorage.setItem('qzScale', JSON.stringify({ vendorId:
object.vendorId ,product: object.product , manufacturer:
object.manufacturer}));
break;
}
}
})
Many thanks for your continued assistance to me and others on this forum!!
Harry
On Wednesday, March 6, 2019 at 4:18:00 AM UTC-8, Sander Elias wrote:
>
> Hi Harry,
>
> I took a closer look to your screenshot. (BTW, pasting snippets as code
> makes it easier to spot issues and help you)
> It is a 'this' problem indeed.
> In JS, each function had it's own 'this' That means the 'this' in the
> function, is not your class. Hence the error.
> Replace the function with an arrow function, and your problem will be gone.
>
> .then( devices => this.choseScale(devices))
>
> should do the trick.
>
> Regards
> Sander
>
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