custom parser for multiple keys

[tonyxiao]

It's possible to implement a custom parser for a single key, but sometimes it is super handy to have a parser that transforms values from multiple keys together into the desired format.

[franky47]

Do you have an example?

You can kind of get there with useQueryStates, and declaring an object of parsers for the individual keys:

const searchParamsParsers = {
  page: parseAsInteger.withDefault(1),
  modalOpen: parseAsBoolean.withDefault(false),
  search: parseAsString
}

const [{ page, modalOpen, search }, updateSearchParams] = useQueryStates(searchParamsParsers)

const nextPage = () => updateSearchParams(state => ({
  page: state.page + 1
  // Partial update: other search params keep their values
}))

One downside to this is that every key is parsed individually. It would not help in cases where you need key foo to have a particular set of values when bar has a specific value. Adding a level of validation on the resulting object could be a good feedback to add to #446.