Request to add allowSingleLineArrow flag for brace-style

What rule do you want to change?

brace-style

Does this change cause the rule to produce more or fewer warnings?

Fewer

How will the change be implemented? (New option, new default behavior, etc.)?

I propose that a new option be add to the rule. The option would be allowSingleLineArrow, boolean, defaulting to false.

Please provide some example code that this change will affect:

functionWithCallback((var1) => { doSomethingWithoutAReturn(); });

What does the rule currently do for this code?

The following error is thrown:

error  Statement inside of curly braces should be on next line             brace-style

What will the rule do after it’s changed?

If allowSingleLineArrow is set to true, the preceding code would be allowed. However, the following code would still error:

if (a === b) { doSomething(); }

Are you willing to submit a pull request to implement this change?

Yes

[jthomerson]

@not-an-aardvark I appreciate your clear explanation, but I disagree with your viewpoint that it’s overly specific. I think many folks have a brace style for things like conditionals, functions, and other true block elements where they don’t want a single line, but they’re willing to allow a single line for arrow functions for brevity.

For example, in our standards, we have this:

if (someCondition) { weDoNotWantConditionalBlocksToBeOnSingleLines(); }
becauseWhenYouScanTheCodeYouMightThinkThisIsConditional();

On the other hand, we allow it for arrow functions because it’s clear when you see an arrow function that you need to look at the function body - to the right. Generally the locations arrow functions are used, you’re not likely to misread something in vertical scanning (like you might in the previous example).

We actually did already create a forked version of this rule in eslint-plugin-silvermine. It was only a few lines of change from the one that’s included in core (as you see in the PR #11227). We’d greatly appreciate if you would consider including it in core. Thanks!

[not-an-aardvark]

Hi, sorry about the lack of activity here. You might be interested in eslint-rule-composer – it’s a tool that would allow you to make some minor changes to rules for your project without forking the whole thing, and I think it would work well for a change like this.