test: Move relevant e2e tests to be unit tests (#802)

.vscode/settings.json

@@ -1,4 +1,6 @@
 {
+  "editor.tabSize": 2,
+  "editor.insertSpaces": true,
   "githubPullRequests.queries": [
     {
       "label": "Backlog",

packages/nuqs/package.json

@@ -156,6 +156,7 @@
     "@types/react": "catalog:react19",
     "@types/react-dom": "catalog:react19",
     "@vitejs/plugin-react": "^4.3.3",
+    "@vitest/coverage-v8": "^2.1.8",
     "next": "15.0.3",
     "react": "catalog:react19",
     "react-dom": "catalog:react19",

packages/nuqs/src/useQueryState.test.ts

@@ -0,0 +1,162 @@
+import { act, renderHook } from '@testing-library/react'
+import { describe, expect, it, vi } from 'vitest'
+import {
+  withNuqsTestingAdapter,
+  type OnUrlUpdateFunction
+} from './adapters/testing'
+import { parseAsArrayOf, parseAsJson, parseAsString } from './parsers'
+import { useQueryState } from './useQueryState'
+
+describe('useQueryState: referential equality', () => {
+  const defaults = {
+    str: 'foo',
+    obj: { initial: 'state' },
+    arr: [
+      {
+        initial: 'state'
+      }
+    ]
+  }
+
+  const useTestHookWithDefaults = (
+    { defaultValue } = { defaultValue: defaults.str }
+  ) => {
+    const str = useQueryState('str', parseAsString.withDefault(defaultValue))
+    const obj = useQueryState(
+      'obj',
+      parseAsJson<any>(x => x).withDefault(defaults.obj)
+    )
+    const arr = useQueryState(
+      'arr',
+      parseAsArrayOf(parseAsJson<any>(x => x)).withDefault(defaults.arr)
+    )
+    return { str, obj, arr }
+  }
+
+  it('should have referential equality on default values', () => {
+    const { result } = renderHook(useTestHookWithDefaults, {
+      wrapper: withNuqsTestingAdapter()
+    })
+    const { str, obj, arr } = result.current
+    expect(str[0]).toBe(defaults.str)
+    expect(obj[0]).toBe(defaults.obj)
+    expect(arr[0]).toBe(defaults.arr)
+    expect(arr[0][0]).toBe(defaults.arr[0])
+  })
+
+  it('should keep referential equality when resetting to defaults', async () => {
+    const { result } = renderHook(useTestHookWithDefaults, {
+      wrapper: withNuqsTestingAdapter({
+        searchParams: {
+          str: 'foo',
+          obj: '{"hello":"world"}',
+          arr: '{"obj":true},{"arr":true}'
+        }
+      })
+    })
+    await act(() => {
+      const { str, arr, obj } = result.current
+      str[1](null)
+      obj[1](null)
+      return arr[1](null)
+    })
+    const { str, arr, obj } = result.current
+    expect(str[0]).toBe(defaults.str)
+    expect(obj[0]).toBe(defaults.obj)
+    expect(arr[0]).toBe(defaults.arr)
+    expect(arr[0][0]).toBe(defaults.arr[0])
+  })
+
+  it('should keep referential equality when unrelated keys change', async () => {
+    const { result } = renderHook(useTestHookWithDefaults, {
+      wrapper: withNuqsTestingAdapter({
+        searchParams: {
+          str: 'foo',
+          obj: '{"hello":"world"}'
+          // Keep arr as default
+        }
+      })
+    })
+    const initialObj = result.current.obj[0]
+    const initialArr = result.current.arr[0]
+    await act(() => {
+      const { str } = result.current
+      return str[1]('bar')
+    })
+    const { str, obj, arr } = result.current
+    expect(str[0]).toBe('bar')
+    expect(obj[0]).toBe(initialObj)
+    expect(arr[0]).toBe(initialArr)
+  })
+
+  it('should keep referential equality when default changes for another key', () => {
+    const { result, rerender } = renderHook(useTestHookWithDefaults, {
+      wrapper: withNuqsTestingAdapter()
+    })
+    expect(result.current.str[0]).toBe('foo')
+    rerender({ defaultValue: 'b' })
+    const { str, obj, arr } = result.current
+    expect(str[0]).toBe('b')
+    expect(obj[0]).toBe(defaults.obj)
+    expect(arr[0]).toBe(defaults.arr)
+    expect(arr[0][0]).toBe(defaults.arr[0])
+  })
+})
+
+describe('useQueryState: clearOnDefault', () => {
+  it('honors clearOnDefault: true by default', async () => {
+    const onUrlUpdate = vi.fn<OnUrlUpdateFunction>()
+    const { result } = renderHook(
+      () => useQueryState('test', parseAsString.withDefault('default')),
+      {
+        wrapper: withNuqsTestingAdapter({
+          searchParams: '?test=init',
+          onUrlUpdate
+        })
+      }
+    )
+    await act(() => result.current[1]('default'))
+    expect(onUrlUpdate).toHaveBeenCalledOnce()
+    expect(onUrlUpdate.mock.calls[0]![0].queryString).toEqual('')
+  })
+
+  it('supports clearOnDefault: false (hook level)', async () => {
+    const onUrlUpdate = vi.fn<OnUrlUpdateFunction>()
+    const useTestHook = () =>
+      useQueryState(
+        'a',
+        parseAsString.withDefault('default').withOptions({
+          clearOnDefault: false
+        })
+      )
+    const { result } = renderHook(useTestHook, {
+      wrapper: withNuqsTestingAdapter({
+        searchParams: '?a=init',
+        onUrlUpdate
+      })
+    })
+    await act(() => result.current[1]('default'))
+    expect(onUrlUpdate).toHaveBeenCalledOnce()
+    expect(onUrlUpdate.mock.calls[0]![0].queryString).toEqual('?a=default')
+  })
+
+  it('supports clearOnDefault: false (call level)', async () => {
+    const onUrlUpdate = vi.fn<OnUrlUpdateFunction>()
+    const useTestHook = () =>
+      useQueryState(
+        'a',
+        parseAsString.withDefault('default').withOptions({
+          clearOnDefault: true
+        })
+      )
+    const { result } = renderHook(useTestHook, {
+      wrapper: withNuqsTestingAdapter({
+        searchParams: '?a=init',
+        onUrlUpdate
+      })
+    })
+    await act(() => result.current[1]('default', { clearOnDefault: false }))
+    expect(onUrlUpdate).toHaveBeenCalledOnce()
+    expect(onUrlUpdate.mock.calls[0]![0].queryString).toEqual('?a=default')
+  })
+})