Check for missing options / databaseURL on emulator start

[Hoppi164]

Description

Bug Fix
When using firebase emulators Realtime Database throws an error due to app.options not existing.
I've found adding an extra check to the database constructor stops this error, and results in the emulator starting up correctly.

Code sample

Instead of
if (app && app.options.databaseURL.startsWith('http:'))
I've added
if ( app && app.options && app.options.databaseURL && app.options.databaseURL.startsWith('http:') )

Note: I've deliberately not used the modern ES6 optional chaining.
This syntax would be much cleaner, but is not supported by your lowest node version.
app?.options?.databaseURL?.startsWith('http:')

[taeold]

Thank you for your great contribution!

Can you add an entry in the CHANGELOG to describe the bug fix?

[taeold]

One more change and we should 🚢

[Hoppi164]

No problem.
Let me know if there's anything else you need me to change :)

[taeold]

@Hoppi164 It looks like the linter is failing - can you run npm run lint or npm run format to fix the tests?

[Hoppi164]

Hi @taeold I've run format:fix and removed the extra spacing i had on the if statement which the linter didn't like.
I've pushed this as another commit.

(note: there was a few other lint warnings in unrelated files, i've not corrected these as it seems out-of-scope for this PR)

[taeold]

lgtm - thank you for your contribution (and your patience!)

[Hoppi164]

No problem at all!
and thanks for all your help 😄
Let me know if there's anything else you need me to do..