Encode object as associative array

[link365dev]

Source: {order:{id: 'asc', date: 'desc'}}

Expected Result: order[id]=asc&order[date]=desc

I tried: JSON.stringify({order:{id: 'asc', date: 'desc'}}, {arrayFormat: 'index'})
but it gave me: {"order":{"id":"asc","date":"desc"}}

If this already supported, what option should I provide?

[sindresorhus]

That's not supported and not something I want to support. It comes with way too many problems. I would recommend https://github.com/ljharb/qs instead if you need that.