There's a node module, but this is a quick hack to do it. Relatively low cost if this function isn't getting called too much. Combining this + some basic memoiz

There's a node module, but this is a quick hack to do it. Relatively low cost if this function isn't getting called too much. Combining this + some basic memoization would probably be the easiest and most performant solution. I imagine you're usually at most receiving events from a single origin.