RlxJS

Description

RlxJS provides error handling functions inspired by rust like Some, None, Ok, Err.

Licensing

Released under the MIT License. See the LICENSE file for further details.

Installation

In shell execute

npm install rlx-js

Or update package.json to include a dependency on

"dependencies": {
  "rlx-js": "0.2.x"
}

Samples

Sample echo program

import { Some, None } from 'rlx-js';

const getArg = () => process.argv.length > 2 ? Some(process.argv[2]) : None();
const message = getArg().mapOrElse(() => "Missing Argument", msg => `Echo: ${msg}`);
console.log(message);

Promise helpers

import { Ok, Err, FlattenResult } from 'rlx-js';

const fetchData = async (url) => {
  const res = await fetch(url);
  if (res.ok) {
    return Ok(res);
  }
  return Err(`Invalid status ${res.status}`);
};

const validateContentType = (res) => {
  const contentType = res.headers.get('content-type');
  if (contentType.includes('application/json')) {
    return Ok(res);
  }
  return Err(`Invalid content type ${contentType}`);
};

const loadText = async (res) => {
  const text = await res.text();
  return text;
};

const text = await FlattenResult(fetchData('...'))
  .andThen(validateContentType)
  .map(loadText)
  .unwrapOrElse(err => err);
console.log(text);

Additional usage

For additional usage see Option and Result tests.