Unexceptional

Exception safe functions and promises by converting thrown errors to values (like Go and Lua). See this gist for background.

NOTE: This meant initially developed for usage together with async/await and function*/yield, so all results are converted to promises (see the source in index.js for more info).

Usage examples

Safe(r) functions:

const { safeFunction } = require('unexceptional');
 
function iThrowThingsSometimes(val, shouldThrow) {
  if (shouldThrow) {
    throw new Error('Something went wrong');
  } else {
    return val;
  }
}
 
const iDontThrowAnyMore = safeFunction(iThrowThingsSometimes);
 
async function main() {
  const [error, result] = await iDontThrowAnyMore(50);
  // error === undefined
  // result === 50
 
  if (error) {
    // handle error as a value or ignore
  }
 
  const [error2, result2] = await iDontThrowAnyMore(50, true);
  // error2 === Error('Something went wrong');
  // result2 === undefined
 
  if (error2) {
    // handle error as a value or ignore
  }
}
 
main();

Safe(r) promises:

const { safePromise } = require('unexceptional');
 
function iRejectSometimes(val, shouldReject) {
  return new Promise(function(resolve, reject) {
    if (shouldReject) {
      reject(new Error('Something went wrong'));
    } else {
      resolve(val);
    }
  });
}
 
async function main() {
  const [error, result] = await safePromise(iRejectSometimes(50));
  // error === undefined
  // result === 50
 
  if (error) {
    // handle error as a value or ignore
  }
 
  const [error2, result2] = await safePromise(iRejectSometimes(50, true));
  // error2 === Error('Something went wrong');
  // result2 === undefined
 
  if (error2) {
    // handle error as a value or ignore
  }
}