Implements Transactions in Firestore

[evandrobubiak]

• Implements Transactions for Firestore Transactions in Firestore #59
• Implements error handling for Firestore errors.
• Created some tests for Transactions.

[CLAassistant]

All committers have signed the CLA.

[labrom]

I think the following would be a more defensive style:

var attempts = 0;
while(++attempts <= maxAttempts) {

and starting line 222:

if (attempts >= maxAttempts) {
  return Future.error(...);
}

[rrousselGit]

I appreciate, but for the sake of maintenance we're trying to stick to a port of the official NodeJS implementation as much as possible.

Cf https://github.com/googleapis/nodejs-firestore/blob/07a88420062c428b04d61638c6ba432422e01652/dev/src/transaction.ts#L79
https://github.com/googleapis/nodejs-firestore/blob/07a88420062c428b04d61638c6ba432422e01652/dev/src/transaction.ts#L582

Do you mind updating your PR such that it is a port of the original code?

[evandrobubiak]

I appreciate, but for the sake of maintenance we're trying to stick to a port of the official NodeJS implementation as much as possible.

Cf https://github.com/googleapis/nodejs-firestore/blob/07a88420062c428b04d61638c6ba432422e01652/dev/src/transaction.ts#L79 https://github.com/googleapis/nodejs-firestore/blob/07a88420062c428b04d61638c6ba432422e01652/dev/src/transaction.ts#L582

Do you mind updating your PR such that it is a port of the original code?

Got it. I'll do my best to maintain compatibility. Thansk for the feed back.

[rrousselGit]

Thanks! I understand that this is quite a big change.

[evandrobubiak]

I will close this requeset and will open a new one with all new code based on NodeJS official implementation.