array.filter with async/await

I can never remember how to filter arrays in JavaScript when I need to use await to run a method.

The answer is that array.filter does not support async, so we have to use array.reduce instead. Here's an example of how it works:

javascript
let values = ["another", "word", "here"];
values = await values.reduce(async (acc, v) => {
  const result = await hasFourLetters(v);
  // If our async method didn't return true, return the current list
  // *without* this new entry
  if (!result) {
    return acc;
  }
  // Otherwise add this value to the list
  return (await acc).concat(run);
}, []);
// values = ["word", "here"]