@thomsonbw I've also stumbled on this problem, the unfortunate issue is there is no standard way of handling arrays in query strings, there's a whole discussion about this here https://stackoverflow.com/questions/6243051/how-to-pass-an-array-within-a-query-string. I wonder if it might make sense to have a config that allows the end user to specify how they'd like their arrays processed

@eokoneyo we effectively had a config option before cross-fetch. You could set the arrayFormat in the o2g requestOptions object and it would be passed through to the underlying package, but the current code doesn't provide similar flexibility.

@thomsonbw Sorry for the very late reply. I'm also sorry that this functionality was lost. I'll try to look into this but if any of you have suggestions on how this could be resolved, I'd love to know.

@thomsonbw, I have opened a Pull request that adds an option for one of the other formats #453

It's true that there are many ways to define arrays in query strings, but URLSearchParams API uses the "repeat" format:

const q = new URLSearchParams()
q.append("test", "one")
q.append("test", "two")
q.append("test", "three")
q.toString() === "test=one&test=two&test=three"

It should at the very least support that.