There is more here that is likely to cause problems in the future. One is the author's use of var instead of let or const. var continues to work but most JS devs have linters that ban the use of var. The issue is, var has function scope, not brace scope. Most non-JS devs coming from other languages will eventually run into this issue.
Another issue porting native apps is, native apps are compiled for a specific platform and hardcoded to that platform's conventions. A good example of this is hardcoding Ctrl-C (copy), Ctrl-V (paste) at compile time, which maybe works on Linux and Windows
but doesn't work on Mac.
IIRC the way you're supposed to handle this on the web is listen for copy and paste events. AFAIK Unity has this issue. They hard coded Ctrl-C, Ctrl-P and so copy and paste don't work on Mac. Most games don't need copy and paste but once in a while someone does something that does need it, then exports to the web and runs into this issue.
Another issue porting native apps is, native apps are compiled for a specific platform and hardcoded to that platform's conventions. A good example of this is hardcoding Ctrl-C (copy), Ctrl-V (paste) at compile time, which maybe works on Linux and Windows but doesn't work on Mac.
IIRC the way you're supposed to handle this on the web is listen for copy and paste events. AFAIK Unity has this issue. They hard coded Ctrl-C, Ctrl-P and so copy and paste don't work on Mac. Most games don't need copy and paste but once in a while someone does something that does need it, then exports to the web and runs into this issue.