Concurrency issue

[rexshijaku]

This issue was reported by J.M via email:

Hello,

I have encountered some problems when I use PDFBarcodeJS. When the concurrency call program, the return result is always the same. Barcode is different in each PDF file,I guess this is not a problem caused by Closure.
I look forward to getting help.

After some research I found out that,

The concurrency issue is caused by decodeSingle function of QuaggaJS mentioned here : serratus/quaggaJS#135 . A solution looks like is provided here: ericblade/quagga2#171 , if this is the only solution, then a major update (from quagga to quagga2) would be necessary.

[ericblade]

hey just noticed this linked to my issues :-) Yeah, original Quagga concurrency system was very very broken, if workers were enabled. If you have to use the original, disable web workers, and it'l probably still work right, but you should be able to for the most part just drop quagga2 in as a replacement, with very few changes, unless you still need to support ancient browsers or node versions that maybe i've dropped support for.