📎 Add configuration option to remove semicolons

[michaelhays]

Description

Prettier has the option to remove semicolons from your code, except for in certain instances to prevent changing the meaning of the code.

It would be great to have this as a configuration option for Rome, particularly to help the adoption rate for existing codebases that don't use semicolons.

(Creating this issue as a continuation of a discussion in this project, to track interest in adding this option)

[sebmck]

This has been a much requested feature. @rome/staff How hard would this be to implement?

[SuperchupuDev]

would this also add the ability to add semicolons?

[sebmck]

@SuperchupuDev I'm not sure I know what that means? This issue is for a configuration option that causes semicolons to be omitted when they aren't necessary. Similar to the prettier option.

[SuperchupuDev]

nevermind, i was talking about something like the semi option from prettier to add instead of removing semicolons even if they aren't necessary, but looks like rome already does the same by default. maybe the configuration option described by this issue could be a semicolon option (that can be set to false) instead of a no-semicolon option? sounds more intuitive

[MichaReiser]

This has been a much requested feature. @rome/staff How hard would this be to implement?

I don't expect it to be too complicated. It's probably a day or two of work.

This is prettier's logic that we can us as a starting point.

https://github.com/prettier/prettier/blob/199a1bb38929c72861ead3cf44978a895eba65bb/src/language-js/print/statement.js#L89-L157

Let's see how today goes. Maybe I'll find some time to look into it.

[ysageev]

I love the idea of Rome but cannot use the VS Code extension because semicolons. ☹️

[michaelhays]

They clearly understand the need for this, please be patient!

Just leave a :+1: on this issue to express your support.

[sebmck]

Draft PR now open from @MichaReiser in #3702 🤯🥳

[MichaReiser]

Could I ask you to vote for the preferred positioning of semicolons in the cases where the semicolon is required? It would help me to decide on the formatting that Rome should implement.

[alistairholt]

Just wanted to say that it's been great to see how promptly and professionaly this was actioned ❤️

[MichaReiser]

Just wanted to say that it's been great to see how promptly and professionaly this was actioned ❤️

Thank you! I plan to push a pre-release tomorrow and would appreciate it if you could try it and report any issues related to the new semicolons options. I'll post some more detailed instructions tomorrow

[MichaReiser]

I've published a nightly Rome release (extension and CLI) a few minutes ago. Could you try the new version and report any semicolon-related issues (feel free to tag me)?

npm i rome@nightly
npx rome format --semicolons=as-needed <paths>

or create a rome configuration

npx rome init 

and set the option in the rome.json file

{
  "javascript": {
    "formatter": {
      "semicolons": "asNeeded"
    }
  }
}

and then run npx rome format <paths>

Thanks!

[ysageev]

Pre-release extension is super fast and no semicolons in sight. 🕺

With the CLI (which I don't really use), I get:

I'm not sure if I'm reading it correctly, but looks like it wants to put semicolons in.

[LinusU]

@ysageev how are you configuring/running rome? It seems like it also wants to change spaces to tabs, so it might not be picking up your config...

[ysageev]

My rome.js. I know it is picking up the config because the linter does not flag the disabled rules.

   "linter": {
      "enabled": true,
      "rules": {
         "recommended": true,
         "security": {
            "noDangerouslySetInnerHtml": "off"
         },
         "a11y": {
            "useKeyWithClickEvents": "off"
         },
         "correctness": {
            "noArguments": "off"
         }
      }
   },
   "javascript": {
      "formatter": {
         "semicolons": "asNeeded"
      }
   }
}

[MichaReiser]

Thanks for giving it a try!

Pre-release extension is super fast and no semicolons in sight. 🕺

With the CLI (which I don't really use), I get:

Why are there elephants at the end of every line? 😆

I'm not sure if I'm reading it correctly, but looks like it wants to put semicolons in.

Seems like. What's the command you run (ci?), and do you run it in the root folder of your project (the folder that contains the rome.json)?

[ysageev]

Seems like. What's the command you run (ci?), and do you run it in the root folder of your project (the folder that contains the rome.json)?

Aha! You are right. I didn't want to format all of my files in ./src, so I cd'd into /src/components/data and ran the file on Aggregate.js.

When instead I now ran npx rome format ./src/components/data/Aggregate.js I got the correct result:

Why are there elephants at the end of every line? 😆

I'm running on Git bash on Windows 10. I thought they were weird percent symbols that signal some special EOL to the formatter. But, on zooming in, they are indeed elephants, which are way better.

Definitely keep the elephants.

[LinusU]

@MichaReiser it seems to work great! However, our code base didn't currently use any "necessary" semicolons, so I cannot comment on that part.

Our code base isn't currently using Standard, but I'm interested in switching to Rome. In the end, it was too many changes to switch right now (it's a big project, and I don't want to mess up the git blame too much). But I'll be following along enthusiastically, and when the linter is ready to replace ESLint for us I'll make the switch to the format tool as well!

[ematipico]

@MichaReiser it seems to work great! However, our code base didn't currently use any "necessary" semicolons, so I cannot comment on that part.

Our code base isn't currently using Standard, but I'm interested in switching to Rome. In the end, it was too many changes to switch right now (it's a big project, and I don't want to mess up the git blame too much). But I'll be following along enthusiastically, and when the linter is ready to replace ESLint for us I'll make the switch to the format tool as well!

To not mess up git blame, you can use these kinds of files: https://github.com/rome/tools/blob/main/.git-blame-ignore-revs

They are really useful. We also contracted these kinds of huge changes (switch from tabs to spaces). I hope it helps!

[michaelhays]

@MichaReiser I just tested the nightly build on my existing codebase of ~50,000 LOC, and it works perfectly! No changes whatsoever in semicolons from the prettier output.

Really impressive work :)