super small code polish

[shunjizhan]

No description provided.

[jacogr]

There is actually method behind this madness - with the ?. babel generates horrible code for environments aka "a complete overkill for method availability checks", so generally we try and stay away from the operator.

This is the actual compiled output after the change is made -

      var _api$rpc$system;

      if (!((_api$rpc$system = api.rpc.system) !== null && _api$rpc$system !== void 0 && _api$rpc$system.dryRun)) {
        throw new Error('The system.dryRun RPC call is not available in your environment');
      }

This applies to at least in the api and the utils, there has actually been a conscious effort to not use it - however it certainly have not been consistently removed all-over polkadot-js repos. If left to the engine in all cases, it would be less messy, but we are not quite at that point with JS support everywhere as of yet.

[wirednkod]

Did NOT know about that.. Thank you @jacogr

[shunjizhan]

There is also similar concern about for ... of since it transpiles to generators. I guess there is always a tradeoff between better performance and cleaner source code.

Personally I am more into cleaner code, because of two reasons:

• we don't really need to read the prod es5 code, so its ok to be messy
• the "performance downgrade" introduced by generator or more messy generated code is trivial for an app like this, where internet traffic takes much longer than code running (for frontend prod code this might be a small concern though)

[shunjizhan]

But either way I think some eslint rule to enforce the style (force optional chaining/no optional chaining) would be great

[jacogr]

There are no eslint (nor ts-eslint) rules to deny these. Also as mentioned, in UI-code, due to what you mentioned above, it has not been a "rule" and is certainly used a lot. (The API and util is very different from "UI code")

In general, these are not that bad in the PR form, where it becomes hairy and worth screaming is when doing a?.b?.c?.d. So each time I use one of these, my brain just screams at me since it know what it causes :)

However, it is actually fixable with a babel == null or != null output with assumptions, specifically noDocumentAll: true - that would remove any "damn, I'm writing really bad stuff now" concerns that causes minor brain explosions. (And would apply to all repos equally if added to the linked config).

With that in and non-hairy outputs, there are actually ts-eslint rules that can enforce the usage of these. (Which would certainly be ok in that case)

[shunjizhan]

sounds great, so I am closing this PR as it's not the desired syntax

[jacogr]

Feel free to re-open, adjusted the babel outputs slightly with https://github.com/polkadot-js/dev/pull/827/files#diff-e46f7bc448773ef1bc430c11187663a5431bc8d7a67aba417675b2e31f3e8cf1R6-R7

The above now certainly removes my issues with the outputs, especially on those pesky longer items, it is no no worse than doing it "manually".

[polkadot-js-bot]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.