How to handle the fact that js and js libs are throwing exceptions all over?

Here’s an example function to wrap an external function that might throw an error.

let tryCatch = fn => {
  try {
    let t = fn()
    Some(t)
  } catch {
  | _ => None
  }
}

@module("./foo.mjs")
external fn: unit => int = "fn"

Console.log(tryCatch(fn))

// foo.mjs
export let fn = () => {
    throw new Error('Error');
}

This will never throw and just returns None.

You can also do something similar with a result type if you want to keep track of the error.

You don’t need to do this everywhere, just at a few key points in the program where you don’t want to throw an exception.