Add more function features

[ghost]

The following features would be appreciated:

max-function-line-count: A line limit for functions.

Add some parameters to max-file-line-count so that the line count can ignore lines containing comments, or empty lines, for example.

single-return: Functions can only contain one return statement if this is set to true (some argue that long functions with multiple return statements can be hard to follow).

[johnwiseheart]

Hi @seanhly, can you please make a separate issue for each rule that you would like?

[thorn0]

There already exists #3549 about max-function-line-count / max-func-body-length.

[JoshuaKGoldberg]

single-return

-1 to a built-in preference for a single return. I find it easier to read code that has minimal nesting of conditionals.

function sample(input) {
    if (isInvalid(input)) {
        return invalidValue;
    }

    const first = runFirst(input);
    const last = runLast(input, first);

    return processLast(last);
}

[ghost]

I agree, your example looks like fine code.

I think when I was writing this I was in the process of refactoring a method with dozens of exit points (not safe guards, just arbitrary return statements), and when I wanted to do something simple like "print this when the method returns", I had to edit a lot more than one line. It seems clearer to me now the problem was with long functions rather than multiple return statements.

If a "single-return" rule or "max-return-statements" rule is added, some code perfectionist with quirks out there is bound to use it, which I find a little amusing. TSLint in a team project is like the code implementation of passive-aggressive behavior, and always leads to interesting debates when someone notices their favorite funky way to do something doesn't even make it past the linter to compile. But I digress, "single-return" may have no real use.

[JoshuaKGoldberg]

Note: per #4534, this issue will be closed in less than a month if no PR is sent to add the rule. If you really need the rule, custom rules are always an option and can be maintained outside this repo!

[JoshuaKGoldberg]

💀 It's time! 💀

TSLint is being deprecated and no longer accepting pull requests for new rules. See #4534. 😱

If you'd like to see this rule implemented, you have two choices:

• Recommended: Use typescript-eslint to lint your TypeScript code with ESLint ✅
• Legacy: Write it as a custom TSLint rule 🤷‍♂️

👋 It was a pleasure open sourcing with you!

If you believe this message was posted here in error, please comment so we can re-open the issue!

[JoshuaKGoldberg]

🤖 Beep boop! 👉 TSLint is deprecated 👈 (#4534) and you should switch to typescript-eslint! 🤖

🔒 This issue is being locked to prevent further unnecessary discussions. Thank you! 👋