result-js

A simple npm package that implements the Option and Result types from Rust.

npm install @shiguww/result-js

Usage

// index.ts
const JSONParse = <T>(s: string) => JSON.parse(s) as T;
const readfile = Result.wrap((path: string) => fs.readFile(path, "utf8"));

const pkg = await readfile("package.json")
  .then((res) => res.chain((s) => JSONParse<{ version: string }>(s)))
  .then((res) => res.inspectErr(() => console.log("Couldn't parse package.json")))
  .then((res) => res.catch(() => null))
  .then((res) => res.unwrap());

if (pkg !== null) {
  console.log(`package.json version: ${pkg.version}`);
}