Node.js giving UnhandledPromiseRejectionWarning, even for code that doesn't have an unhandled promise rejection

[DragonOsman]

I tried to run the parcel index.html command to build country-currency-map (a Node.js module), but I had an "UnhandledPromiseRejectionWarning" even though the library reportedly doesn't have an unhandled promise rejection. Trying to do the "Getting Started" example on the Parcel.js page has the same result. I already uninstalling and reinstalling Node.js and I even installed the latest version. Still doesn't work.

I'm using Windows 10. I also have WSL. When I try to run the commands in the bash shell, though, I get an error saying "parcel: node: not found" even though I did install Node.js in WSL mode as well. And it's also on my PATH.

[evanlucas]

Setting the NODE_OPTIONS environment variable to --trace-warnings should print out a stack trace for unhandled rejections (depending on what version of node you are using)

[DragonOsman]

Sorry for noob-question, but: Where do I set that?

[evanlucas]

@DragonOsman apologies, but I'm not a Windows user. A quick google search shows this. Hopefully, that helps! Thanks! :]

[gireeshpunathil]

you could also set it on the command prompt:
set NODE_OPTIONS="--trace-warnings" as a one time business (the setting expires along with the shell session).

More simpler, you could add the option in-line to the node command (the setting lives only for the node command)

D:\home\gireesh>cat foo.js
require('util').debug('hello')

D:\home\gireesh>node --trace-warnings foo.js
DEBUG: hello
(node:11724) [DEP0028] DeprecationWarning: util.debug is deprecated. Use console.error instead.
    at Object.<anonymous> (D:\home\gireesh\foo.js:1:79)
    at Module._compile (module.js:662:30)
    at Object.Module._extensions..js (module.js:673:10)
    at Module.load (module.js:575:32)
    at tryModuleLoad (module.js:515:12)
    at Function.Module._load (module.js:507:3)
    at Function.Module.runMain (module.js:703:10)
    at startup (bootstrap_node.js:193:16)
    at bootstrap_node.js:665:3

closing as answered, please let me know if you have additional questions.