[Research] URLSearchParams array support

[franky47]

Search params can appear more than once in the query string, like so: ?foo=bar&foo=baz

This reflects in URLSearchParams under a different API:

• getAll to obtain an array of values: ['bar', 'baz']
• get would only return the first entry (specification): 'bar'
• append does what it says, and adds a new entry when updating (eg: .append('foo', 'qux') will give ?foo=bar&foo=baz&foo=qux)
• set overrides any existing value (eg: .set('foo', 'qux') will give ?foo=qux)

In order to support this, some refactoring of the parsers, hook logic, and type definitions needs to be done, as it only ever worked with one-dimensional values.

Related discussions

• Array querystring output customization. #427

Originally posted by @ianldgs in #481 (comment)

If you have some feedback on a good API for this, I'd love to discuss more about it.

Perhaps a good API that woudn't require a lot of refactoring is:

type StringParser<T> = {
    parse: (value: string) => T | null;
    serialize?: (value: T) => string;
}
type NativeArrayParser<T> = {
    // inspired on `URLSearchParams.prototype.getAll`
    parseAll: (values: string[]) => T[] | null;
    serializeAll?: (values: T[]) => string[];
}

type Parser = StringParser<T> | NativeArrayParser<T>;

Then:

const parseNativeArray = (subParser: StringParser<T>) => {
  parseAll(values: string[]) => values.map(value => subParser.parse(value)),
  serializeAll(values: T[]) => values.map(value => subParser.serialize(value)),
}

useQueryState("id", parseNativeArray(parseAsString));