Fail gracefully if Deno.env is not accessible

[stevekrouse]

At Val Town we block access to Deno.env, which means that LangChain will fail to run. It would be nice if it could wrap calls to Deno.env.get in a try/catch and treat a thrown exception there as you would if the environment variable simply wasn't set.

Alternatively, we could directly folks to using langchain via npm which sometimes succeeds and sometimes fails.

Success:

Fail:

We haven't yet figured out the cause of this intermittent error - let us know if you have any clue to it.

Here's my langChain example val: https://www.val.town/v/stevekrouse.langchainEx. You can view past versions to see what I mean.

[jacoblee93]

This might be related to the second thing:

#1386