fix: useQueryStates does not update values correctly when config chan…

…ges (#908)

packages/docs/src/app/playground/_demos/repro-907/page.tsx

@@ -0,0 +1,57 @@
+// https://github.com/47ng/nuqs/issues/907
+
+'use client'
+
+import { parseAsString, useQueryStates } from 'nuqs'
+import { useState } from 'react'
+
+export default function Home() {
+  const [nuqsConfig, setNuqsConfig] = useState<
+    Record<string, typeof parseAsString>
+  >({
+    p1: parseAsString,
+    p2: parseAsString
+  })
+
+  const [values] = useQueryStates(nuqsConfig)
+
+  return (
+    <>
+      <div className="flex gap-2">
+        <button
+          onClick={() => setNuqsConfig({ p1: parseAsString })}
+          className="border p-2"
+        >
+          Update config (remove one of the keys)
+        </button>
+
+        <button
+          onClick={() =>
+            setNuqsConfig({
+              p1: parseAsString,
+              p2: parseAsString,
+              p3: parseAsString
+            })
+          }
+          className="border p-2"
+        >
+          Update config (add a new key)
+        </button>
+
+        <button
+          onClick={() =>
+            setNuqsConfig({
+              p1: parseAsString,
+              p5: parseAsString
+            })
+          }
+          className="border p-2"
+        >
+          Update config (replace a key)
+        </button>
+      </div>
+      <div>Config keys: {JSON.stringify(Object.keys(nuqsConfig))}</div>
+      <div>Result: {JSON.stringify(values)}</div>
+    </>
+  )
+}

packages/nuqs/src/useQueryStates.test.ts

@@ -346,6 +346,25 @@ describe('useQueryStates: dynamic keys', () => {
     expect(result.current[0].d).toEqual(4)
   })
 
+  it('updating keys also updates the result structure', () => {
+    const useTestHook = (keys: string[] = ['a', 'b']) =>
+      useQueryStates(
+        keys.reduce((acc, key) => ({ ...acc, [key]: parseAsInteger }), {})
+      )
+    const { result, rerender } = renderHook(useTestHook, {
+      wrapper: withNuqsTestingAdapter({
+        searchParams: ''
+      })
+    })
+    expect(result.current[0]).toStrictEqual({ a: null, b: null })
+    rerender(['a']) // remove b
+    expect(result.current[0]).toStrictEqual({ a: null })
+    rerender(['a', 'b', 'c']) // add c
+    expect(result.current[0]).toStrictEqual({ a: null, b: null, c: null })
+    rerender(['a', 'b', 'd']) // remove c, add d
+    expect(result.current[0]).toStrictEqual({ a: null, b: null, d: null })
+  })
+
   it('supports dynamic keys with remapping', () => {
     const useTestHook = (keys: [string, string] = ['a', 'b']) =>
       useQueryStates(

packages/nuqs/src/useQueryStates.ts

@@ -310,6 +310,16 @@ function parseMap<KeyMap extends UseQueryStatesKeysMap>(
     }
     return out
   }, {} as NullableValues<KeyMap>)
+
+  if (!hasChanged) {
+    // check that keyMap keys have not changed
+    const keyMapKeys = Object.keys(keyMap)
+    const cachedStateKeys = Object.keys(cachedState ?? {})
+    hasChanged =
+      keyMapKeys.length !== cachedStateKeys.length ||
+      keyMapKeys.some(key => !cachedStateKeys.includes(key))
+  }
+
   return { state, hasChanged }
 }