Fix error with server side rendering

[tlaverdure]

I'm using idb-keyval in a project that does server side rendering and this was causing some issues server side when this file was imported.

[jakearchibald]

idb-keyval only calls idbReady() when creating a store, right before calling indexedDB.open(dbName). Wouldn't that indexedDB.open call also cause issues server side?

[tlaverdure]

Yes that actually would cause issues as well.

[jakearchibald]

I think the solution here is to guard calls like this so they won't run on the server. I usually have a global like __SERVER__ that's true if it's being run on the server.

[dfahlander]

Hi! It is not uncommon to use fakeIndexedDB to run it on unit tests in plain node.js. Could be argued that the unit tests wouldn't need this workaround anyway, but if they are put into a database layer used from both unit tests and application code, that database layer need to check typeof navigator === 'undefined' before invoking the fix. Not a hard thing to do, but maybe cleaner having the check in the workaround itself.

BTW: Amazing how many details in need to take care of :O
Thanks for providing the fix!