Extract refactors break single-line `if` statements into two lines

[andrewbranch]

Bug Report

🔎 Search Terms

extract function single-line if

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about whether Tang was really invented by NASA

💻 Code

function f() {
  return [].filter(x => {
    if (!x) return false;
  });
}

🙁 Actual behavior

Select the arrow function callback of filter and run “Extract to inner function.” The formatting of the function contents should be the same in the extracted function.

🙂 Expected behavior

function newFunction(): (value: any, index: number, array: any[]) => unknown {
  return x => {
    if (!x)
      return false; // New line added
  };
}

[fatcerberus]

and I reviewed the FAQ for entries about whether Tang was really invented by NASA

lol

[DanielRosenwasser]

brb reading every issue Andrew has filed ever just in case I missed something

[andrewbranch]

You definitely did 😏

[iinicole]

Hi! This is my first time contributing. I would like to try resolving this issue if possible.

[andrewbranch]

Hi @iinicole, take a look at https://github.com/microsoft/TypeScript/blob/main/CONTRIBUTING.md for how to get started. My guess is the fix is likely to be similar to #39280. The first step (after you get the source code cloned, building, and running) will be to write a failing fourslash test case. The PR I just linked contains one you can use for reference. Feel free to ask for help if you get stuck, but how much guidance we can give varies by how busy things are, how close you are to being on the right track, and how complicated the bug ends up being—sometimes these things look easy and end up being difficult; sometimes the opposite happens. If it gets to be overwhelming, no worries; I’d encourage you to look for an issue labeled “Good First Issue” in that case. Good luck and thanks!