fix: Cache the query string in useQueryStates (#631)

The cache key for testing if the query changed 
wasn't being updated in useQueryStates.

This also revealed it being broken in next@14.0.3, 
where the history patching mechanism wasn't working. 
A fix has been added and will be removed in v2 
(where support for those version ranges is dropped).

packages/e2e/cypress/e2e/repro-630.cy.js

@@ -0,0 +1,39 @@
+/// <reference types="cypress" />
+
+describe('Reproduction for issue #630', () => {
+  it('works with useQueryState', () => {
+    runTest('1')
+  })
+  it('works with useQueryStates', () => {
+    runTest('3')
+  })
+})
+
+function runTest(sectionToTry) {
+  cy.visit('/app/repro-630')
+  cy.contains('#hydration-marker', 'hydrated').should('be.hidden')
+  cy.get('#1-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#2-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#3-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#4-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get(`#${sectionToTry}-set`).click()
+  cy.get('#1-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get('#2-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get('#3-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get('#4-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get(`#${sectionToTry}-clear`).click()
+  cy.get('#1-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#2-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#3-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#4-pre').should('have.text', '{"a":null,"b":null}')
+  cy.go('back')
+  cy.get('#1-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get('#2-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get('#3-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.get('#4-pre').should('have.text', '{"a":"1","b":"2"}')
+  cy.go('back')
+  cy.get('#1-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#2-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#3-pre').should('have.text', '{"a":null,"b":null}')
+  cy.get('#4-pre').should('have.text', '{"a":null,"b":null}')
+}

packages/e2e/src/app/app/repro-630/page.tsx

@@ -0,0 +1,79 @@
+'use client'
+
+import { parseAsString, useQueryState, useQueryStates } from 'nuqs'
+import { Suspense } from 'react'
+
+export default function Page() {
+  return (
+    <Suspense>
+      <Client id="1" />
+      <Client id="2" />
+      <Clients id="3" />
+      <Clients id="4" />
+    </Suspense>
+  )
+}
+
+type ClientProps = {
+  id: string
+}
+
+function Client({ id }: ClientProps) {
+  const [a, setA] = useQueryState(
+    'a',
+    parseAsString.withOptions({ history: 'push' })
+  )
+  const [b, setB] = useQueryState(
+    'b',
+    parseAsString.withOptions({ history: 'push' })
+  )
+
+  return (
+    <>
+      <p>useQueryState {id}</p>
+      <pre id={`${id}-pre`}>{JSON.stringify({ a, b })}</pre>
+      <button
+        id={`${id}-set`}
+        onClick={() => {
+          setA('1')
+          setB('2')
+        }}
+      >
+        Set
+      </button>
+      <button
+        id={`${id}-clear`}
+        onClick={() => {
+          setA(null)
+          setB(null)
+        }}
+      >
+        Clear
+      </button>
+      <hr />
+    </>
+  )
+}
+
+function Clients({ id }: ClientProps) {
+  const [params, setParams] = useQueryStates(
+    {
+      a: parseAsString,
+      b: parseAsString
+    },
+    { history: 'push' }
+  )
+  return (
+    <>
+      <p>useQueryStates {id}</p>
+      <pre id={`${id}-pre`}>{JSON.stringify(params)}</pre>
+      <button id={`${id}-set`} onClick={() => setParams({ a: '1', b: '2' })}>
+        Set
+      </button>
+      <button id={`${id}-clear`} onClick={() => setParams(null)}>
+        Clear
+      </button>
+      <hr />
+    </>
+  )
+}

packages/nuqs/src/useQueryStates.ts

@@ -88,6 +88,26 @@ export function useQueryStates<KeyMap extends UseQueryStatesKeysMap>(
     initialSearchParams
   )
 
+  React.useEffect(() => {
+    // This will be removed in v2 which will drop support for
+    // partially-functional shallow routing (14.0.2 and 14.0.3)
+    if (window.next?.version !== '14.0.3') {
+      return
+    }
+    const state = parseMap(
+      keyMap,
+      initialSearchParams,
+      queryRef.current,
+      stateRef.current
+    )
+    setInternalState(state)
+  }, [
+    Object.keys(keyMap)
+      .map(key => initialSearchParams?.get(key))
+      .join('&'),
+    keys
+  ])
+
   // Sync all hooks together & with external URL changes
   React.useInsertionEffect(() => {
     function updateInternalState(state: V) {
@@ -216,6 +236,9 @@ function parseMap<KeyMap extends UseQueryStatesKeysMap>(
     }
     const value = query === null ? null : safeParse(parse, query, key)
     obj[key as keyof KeyMap] = value ?? defaultValue ?? null
+    if (cachedQuery) {
+      cachedQuery[key] = query
+    }
     return obj
   }, {} as Values<KeyMap>)
 }