Eslint migration

[stephen-slm]

Eslint Upgrade #287

This pull request focuses on the migration from semistandard to eslint with standard/standard as the direct rule set for linting the application. By moving to eslint allows future development and migration to Typescript smoother. While also supporting linting, code style enforcement, and support of locating errors.

eslint: https://eslint.org/

Linted Content

Linting has been run throughout the application which has mainly shifted var to const and var to let where applicable. While also correcting string index references to direct references e.g a['test'] to a.test.

Node V8 Support (Breaking Change)

Development of the project will no longer support Node version 8 due to eslint using unsupported JavaScript features. Node V8 is also currently deprecated since 2019-12-31 and this should not be seen as a negative breaking change.

[coveralls]

Coverage remained the same at 86.427% when pulling 9af4205 on stephensli:eslint-migration into f239ac6 on ethereum:master.

[cameel]

The changes look fine to me. The only thing to settle is the node.js v8 support.

Personally, I think it's fine drop it - even v10 is already EOL and the major Solidity frameworks that depend on solc-js already require v12+ themselves. I'd like to get an ack from @chriseth and/or @axic before we go forward with it though.

Also, if we're dropping it, please adjust .circleci/config.yml to remove the job that runs on that version. I'd remove the disabled v4 and v6 as well. And I'd also add a comment explaining that ESLint is the reason behind the v10+ requirement.

[cameel]

I'm marking it as approved since I don't see any problem with dropping v8 and I suspect that @chriseth and @axic will agree. We still need to wait for their approval though - especially because the node-v8 job is marked as a required check and I don't have permissions to remove it from repo settings myself.

I think you can already safely rebase your other PR on this one though.

[cameel]

#566 (comment) was actually meant to go here:

I asked @axic about the PR on the call today. He's going to take a look but one problem he pointed out already is that removal of v8 support is technically a breaking change unfortunately.

Well, maybe we could make a breaking 0.9.x release early?

[cameel]

@axic Reposting this from the chat so that it does not get lost:

This is what I managed to find so far for projects we have listed in #10278

• Waffle: >= v10 or lower (Install fails on Node 9 TrueFiEng/Waffle#28 (comment)))
• Truffle: >= v12 (Drop support for Node v10 trufflesuite/truffle#4135)
• Hardhat: >= v12 (Drop support for Node.js 10 NomicFoundation/hardhat#1760)
• Embark: ???
• Saddle: probably still >= 10, might be lower (Quiet errors from using Node 10 (which is needed to build deps...) compound-finance/saddle#4)

https://en.wikipedia.org/wiki/Node.js#Releases

 8.x    End-of-Life      Carbon       2017-05-30   2019-12-31
 9.x    End-of-Life                   2017-10-01   2018-06-30
10.x    End-of-Life      Dubnium      2018-04-24   2021-04-30
11.x    End-of-Life                   2018-10-23   2019-06-01
12.x    Maintenance LTS  Erbium       2019-04-23   2022-04-30
13.x    End-of-Life                   2019-10-22   2020-06-01
14.x    Active LTS       Fermium      2020-04-21   2023-04-30
15.x    End of Life                   2020-10-20   2021-06-01
16.x    Active LTS       Gallium      2021-04-20   2024-04-30
17.x    Current                       2021-10-19   2022-06-01
18.x    Planned                       2022-04-19   2025-04-30 

[cameel]

@chriseth approved dropping v8 support. This should now be rebased on #572.

[stephen-slm]

@cameel done

[axic]

Why did this miss a bunch of other issues, like single-quotes vs double-quotes, missing semicolons, spacing around function names and object, etc. ?

cc @stephensli @cameel

[stephen-slm]

@axic you are going to have to provide examples, a quick fly over is all good.

The only file that was not linted was: solcjs due to the extension not existing. #566 makes this change.

[axic]

solcjs as you mentioned due to the filename issue, but also test/compiler.js.