diff --git a/jest.config.js b/jest.config.js
index 891fd7628..f98a02e87 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -1,6 +1,6 @@
 module.exports = {
   testEnvironment: 'jsdom',
-  testRegex: '/test/.*\\.test\\.tsx$',
+  testRegex: '/test/.*\\.test\\.tsx?$',
   modulePathIgnorePatterns: ['<rootDir>/examples/'],
   setupFilesAfterEnv: ['<rootDir>/scripts/jest-setup.ts'],
   transform: {
diff --git a/scripts/watch.js b/scripts/watch.js
index 3f7b5164c..2ef46b97d 100644
--- a/scripts/watch.js
+++ b/scripts/watch.js
@@ -5,7 +5,7 @@ const bundle = require('bunchee').bundle
 const childProcess = require('child_process')
 
 const args = process.argv
-const target = args[2]
+const target = args[2] || 'core'
 
 const entryMap = {
   core: {
diff --git a/src/utils/env.ts b/src/utils/env.ts
index c4e757ae5..e59f75c06 100644
--- a/src/utils/env.ts
+++ b/src/utils/env.ts
@@ -1,11 +1,11 @@
 import { useEffect, useLayoutEffect } from 'react'
 import { hasWindow } from './helper'
 
-export const IS_SERVER = !hasWindow || 'Deno' in window
+export const IS_SERVER = !hasWindow() || 'Deno' in window
 
 // Polyfill requestAnimationFrame
 export const rAF =
-  (hasWindow && window['requestAnimationFrame']) ||
+  (hasWindow() && window['requestAnimationFrame']) ||
   ((f: (...args: any[]) => void) => setTimeout(f, 1))
 
 // React currently throws a warning when using useLayoutEffect on the server.
diff --git a/src/utils/helper.ts b/src/utils/helper.ts
index 89fdf6129..f153ef448 100644
--- a/src/utils/helper.ts
+++ b/src/utils/helper.ts
@@ -13,5 +13,5 @@ export const isFunction = (v: any): v is Function => typeof v == 'function'
 export const mergeObjects = (a: any, b: any) => OBJECT.assign({}, a, b)
 
 const STR_UNDEFINED = 'undefined'
-export const hasWindow = typeof window != STR_UNDEFINED
-export const hasDocument = typeof document != STR_UNDEFINED
+export const hasWindow = () => typeof window != STR_UNDEFINED
+export const hasDocument = () => typeof document != STR_UNDEFINED
diff --git a/src/utils/web-preset.ts b/src/utils/web-preset.ts
index 56d346717..6fd71c0f2 100644
--- a/src/utils/web-preset.ts
+++ b/src/utils/web-preset.ts
@@ -11,22 +11,25 @@ import { isUndefined, noop, hasWindow, hasDocument } from './helper'
 let online = true
 const isOnline = () => online
 
+const hasWin = hasWindow()
+const hasDoc = hasDocument()
+
 // For node and React Native, `add/removeEventListener` doesn't exist on window.
 const onWindowEvent =
-  hasWindow && window.addEventListener
+  hasWin && window.addEventListener
     ? window.addEventListener.bind(window)
     : noop
-const onDocumentEvent = hasDocument
-  ? document.addEventListener.bind(document)
-  : noop
+const onDocumentEvent = hasDoc ? document.addEventListener.bind(document) : noop
 const offWindowEvent =
-  hasWindow && window.removeEventListener ? window.removeEventListener : noop
-const offDocumentEvent = hasDocument
+  hasWin && window.removeEventListener
+    ? window.removeEventListener.bind(window)
+    : noop
+const offDocumentEvent = hasDoc
   ? document.removeEventListener.bind(document)
   : noop
 
 const isVisible = () => {
-  const visibilityState = hasDocument && document.visibilityState
+  const visibilityState = hasDoc && document.visibilityState
   if (!isUndefined(visibilityState)) {
     return visibilityState !== 'hidden'
   }
diff --git a/test/unit.test.tsx b/test/unit/utils.test.tsx
similarity index 94%
rename from test/unit.test.tsx
rename to test/unit/utils.test.tsx
index 12cd21d4b..0321d26ce 100644
--- a/test/unit.test.tsx
+++ b/test/unit/utils.test.tsx
@@ -1,9 +1,9 @@
-import { normalize } from '../src/utils/normalize-args'
-import { stableHash as hash } from '../src/utils/hash'
-import { serialize } from '../src/utils/serialize'
-import { mergeConfigs } from '../src/utils/merge-config'
+import { normalize } from '../../src/utils/normalize-args'
+import { stableHash as hash } from '../../src/utils/hash'
+import { serialize } from '../../src/utils/serialize'
+import { mergeConfigs } from '../../src/utils/merge-config'
 
-describe('Unit tests', () => {
+describe('Utils', () => {
   it('should normalize arguments correctly', async () => {
     const fetcher = () => {}
     const opts = { revalidateOnFocus: false }
diff --git a/test/unit/web-preset.test.ts b/test/unit/web-preset.test.ts
new file mode 100644
index 000000000..c7d1bc22f
--- /dev/null
+++ b/test/unit/web-preset.test.ts
@@ -0,0 +1,98 @@
+import { EventEmitter } from 'events'
+
+const FOCUS_EVENT = 'focus'
+const VISIBILITYCHANGE_EVENT = 'visibilitychange'
+
+function createEventTarget() {
+  EventEmitter.prototype['addEventListener'] = EventEmitter.prototype.on
+  EventEmitter.prototype['removeEventListener'] = EventEmitter.prototype.off
+  const target = new EventEmitter()
+
+  return target
+}
+
+function runTests(propertyName) {
+  let webPreset
+  let initFocus
+  const eventName =
+    propertyName === 'window' ? FOCUS_EVENT : VISIBILITYCHANGE_EVENT
+
+  describe(`Web Preset ${propertyName}`, () => {
+    const globalSpy = {
+      window: undefined,
+      document: undefined
+    }
+
+    beforeEach(() => {
+      globalSpy.window = jest.spyOn(global, 'window', 'get')
+      globalSpy.document = jest.spyOn(global, 'document', 'get')
+
+      jest.resetModules()
+    })
+
+    afterEach(() => {
+      globalSpy.window.mockClear()
+      globalSpy.document.mockClear()
+    })
+
+    it(`should trigger listener when ${propertyName} has browser APIs`, async () => {
+      const target = createEventTarget()
+      if (propertyName === 'window') {
+        globalSpy.window.mockImplementation(() => target)
+        globalSpy.document.mockImplementation(() => undefined)
+      } else if (propertyName === 'document') {
+        globalSpy.window.mockImplementation(() => undefined)
+        globalSpy.document.mockImplementation(() => target)
+      }
+
+      webPreset = require('../../src/utils/web-preset')
+      initFocus = webPreset.defaultConfigOptions.initFocus
+
+      const fn = jest.fn()
+      const release = initFocus(fn) as () => void
+
+      target.emit(eventName)
+      expect(fn).toBeCalledTimes(1)
+
+      release()
+      target.emit(eventName)
+      expect(fn).toBeCalledTimes(1)
+    })
+
+    it(`should not trigger listener when ${propertyName} is falsy`, async () => {
+      if (propertyName === 'window') {
+        // window exists but without event APIs
+        globalSpy.window.mockImplementation(() => ({
+          emit: createEventTarget().emit
+        }))
+        globalSpy.document.mockImplementation(() => undefined)
+      } else if (propertyName === 'document') {
+        globalSpy.window.mockImplementation(() => undefined)
+        globalSpy.document.mockImplementation(() => undefined)
+      }
+
+      webPreset = require('../../src/utils/web-preset')
+      initFocus = webPreset.defaultConfigOptions.initFocus
+
+      const fn = jest.fn()
+      const release = initFocus(fn) as () => void
+      const target = global[propertyName]
+
+      // TODO: target?.emit?() breaks prettier, fix prettier format
+      if (target && target.emit) {
+        target.emit(eventName)
+      }
+
+      expect(fn).toBeCalledTimes(0)
+
+      release()
+      if (target && target.emit) {
+        target.emit(eventName)
+      }
+      expect(fn).toBeCalledTimes(0)
+    })
+  })
+}
+
+runTests('window')
+runTests('document')
diff --git a/test/use-swr-local-mutation.test.tsx b/test/use-swr-local-mutation.test.tsx
index 302649da8..81b5ce419 100644
--- a/test/use-swr-local-mutation.test.tsx
+++ b/test/use-swr-local-mutation.test.tsx
@@ -903,7 +903,7 @@ describe('useSWR - local mutation', () => {
         }
 
         startMutation()
-      }, [])
+      }, [mutate])
 
       loggedData.push(data)
       return null