err...

err.js

async function doSomething() {
	return new Promise((resolve, reject) => {
		setTimeout(() => resolve("done!"), 1000)
	});
}

// Rejection case
async function doSomethingBad() {
	return new Promise((resolve, reject) => {
		setTimeout(() => reject("crap!"), 1000)
	});
}

// Exception case
async function throwSomethingBad() {
	return window.test.test;
}
 
async function makeItNice(fn) {
 let result = null;
 let error = null;

 try {
 	result = await fn()
 } catch(e) {
	error = e;
 }
  
  return [result, error];
}

async function test() {
  // REJECT CASE
  /* let [result, error] = await makeItNice(doSomethingBad) */;
  // THROW CASE
  /* let [result, error] = await makeItNice(throwSomethingBad) */;
  // HAPPY CASE
  let [result, error] = await makeItNice(doSomething);
  
  if (error) {
    if (!error.name) {
    	console.log('Err... promise rejected');
    } else {
      console.log("it's a real exception!", error.name);
      
    // bla bla 
    // error.name doesn't exist on rejected promises 
    // ... unless you reject with an object with a name property ofc:D 
    } 
    
    return;
  }
  
  if (result) {
    console.log('Works!', result);
  }
}

test();