convert-to-arrow - codemod for js/ts files.

Codemod to safely convert function declarations into equivalent const arrow-function expressions.

// before
export function getUser<
  // user id type
  ID extends string | number,
>(id: ID): Promise<User> {
  return db.users.find(id)
}

// after (auto-generated)
export const getUser = <
  // user id type
  ID extends string | number,
>(id: ID): Promise<User> => {
  return db.users.find(id)
}

Compatible with TypeScript and JavaScript. See fixtures for more examples

Quick-start (no install required)

run in the root of your repo - converts all files in the current directory and subdirectories:

npx convert-to-arrow

or specify a sub-folder / glob (defaults to **/*.{ts,tsx}):

npx convert-to-arrow src

More path options see advanced usage

Safety checklist

• Commit/stash your work first – revert is instant.
• Run the codemod
• Review the diff
• Run test suite / type-checking
• Check the files for identation changes – the codemod tries to preserve the original formatting, but it may not always succeed.

Advanced usage

The CLI currently exposes one optional directory flag:

Example:

# convert only files under ./src
npx -y convert-to-arrow src

# convert two workspaces
npx -y convert-to-arrow "packages/*/src"

# full glob (quotes required for zsh)
npx -y convert-to-arrow "**/*.tsx"

Contributing / local development

git clone https://github.com/richard-unterberg/convert-to-arrow
cd convert-to-arrow
npm i # install dependencies
npm run lefthook # git hooks
npm run dev # runs the codemod on this project (should convert test/fixtures.ts)
npm run build # build the codemod - see dist

Pull requests & issues are welcome!