Migrate TypeScript/Javascript projects from relative to absolute paths

migrate.exs

relative_to_absolute = fn relative_path, importing_file ->
  Path.expand(relative_path, Path.dirname(importing_file))
  |> String.split("src/")
  |> List.last()
end

Path.wildcard('src/**/*.{ts,tsx}')
|> Enum.each(fn file ->
  IO.puts("Migrating #{file}...")
  contents = File.read!(file)

  migrated =
    contents
    |> String.split("\n")
    |> Enum.map(fn line ->
      Regex.replace(~r/from '(\.\.\/.+?)';/, line, fn _match, relative_path ->
        "from '#{relative_to_absolute.(relative_path, file)}';"
      end)
    end)
    |> Enum.join("\n")

  File.write!(file, migrated)
  IO.puts("DONE")
end)

Example tsconfig:

{
  "compilerOptions": {
    "target": "es2016",
    "module": "commonjs",
    "rootDir": ".",
    "baseUrl": "src",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "noEmit": true,
    "skipLibCheck": true,
    "jsx": "react",
    "types": ["jest"],
    "typeRoots": ["./types", "./node_modules/@types"],
    "paths": {
      "__tests__/*": ["../__tests__/*"]
    }
  },
  "exclude": ["coverage"]
}

Notably the baseUrl is set to src which is where all the imported files live.