diff --git a/.idea/workspace.xml b/.idea/workspace.xml
deleted file mode 100644
index 1ffeaef..0000000
--- a/.idea/workspace.xml
+++ /dev/null
@@ -1,86 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ChangeListManager">
-    <list default="true" id="df737647-19a6-4a5f-88a0-8ce9d29a36c8" name="Changes" comment="">
-      <change beforePath="$PROJECT_DIR$/source/index.ts" beforeDir="false" afterPath="$PROJECT_DIR$/source/index.ts" afterDir="false" />
-    </list>
-    <option name="SHOW_DIALOG" value="false" />
-    <option name="HIGHLIGHT_CONFLICTS" value="true" />
-    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
-    <option name="LAST_RESOLUTION" value="IGNORE" />
-  </component>
-  <component name="Git.Settings">
-    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
-  </component>
-  <component name="MacroExpansionManager">
-    <option name="directoryName" value="hl7nkx35" />
-  </component>
-  <component name="MarkdownSettingsMigration">
-    <option name="stateVersion" value="1" />
-  </component>
-  <component name="ProjectId" id="25cK4TvoIxGKxbzN8247wytmhpC" />
-  <component name="ProjectViewState">
-    <option name="hideEmptyMiddlePackages" value="true" />
-    <option name="showLibraryContents" value="true" />
-  </component>
-  <component name="PropertiesComponent"><![CDATA[{
-  "keyToString": {
-    "WebServerToolWindowFactoryState": "false",
-    "last_opened_file_path": "/Users/wangbinlin/Project/daily_exercise/is",
-    "nodejs_package_manager_path": "npm",
-    "ts.external.directory.path": "/Users/wangbinlin/Project/daily_exercise/is/node_modules/typescript/lib",
-    "vue.rearranger.settings.migration": "true"
-  }
-}]]></component>
-  <component name="RunManager" selected="Node.js.index.js">
-    <configuration name="index.js" type="NodeJSConfigurationType" temporary="true" nameIsGenerated="true" path-to-js-file="$PROJECT_DIR$/source/index.js" working-dir="$PROJECT_DIR$/source">
-      <method v="2" />
-    </configuration>
-    <configuration name="test.js" type="NodeJSConfigurationType" temporary="true" nameIsGenerated="true" path-to-js-file="$PROJECT_DIR$/test/test.js" working-dir="$PROJECT_DIR$/test">
-      <method v="2" />
-    </configuration>
-    <recent_temporary>
-      <list>
-        <item itemvalue="Node.js.index.js" />
-        <item itemvalue="Node.js.test.js" />
-      </list>
-    </recent_temporary>
-  </component>
-  <component name="SpellCheckerSettings" RuntimeDictionaries="0" Folders="0" CustomDictionaries="0" DefaultDictionary="application-level" UseSingleDictionary="true" transferred="true" />
-  <component name="TaskManager">
-    <task active="true" id="Default" summary="Default task">
-      <changelist id="df737647-19a6-4a5f-88a0-8ce9d29a36c8" name="Changes" comment="" />
-      <created>1645820743983</created>
-      <option name="number" value="Default" />
-      <option name="presentableId" value="Default" />
-      <updated>1645820743983</updated>
-      <workItem from="1645820745885" duration="3571000" />
-      <workItem from="1645962952689" duration="7278000" />
-      <workItem from="1646150741729" duration="7294000" />
-      <workItem from="1646315541343" duration="840000" />
-      <workItem from="1646820573494" duration="13927000" />
-      <workItem from="1654745859867" duration="730000" />
-      <workItem from="1654783293999" duration="13454000" />
-    </task>
-    <servers />
-  </component>
-  <component name="TypeScriptGeneratedFilesManager">
-    <option name="version" value="3" />
-    <option name="exactExcludedFiles">
-      <list>
-        <option value="$PROJECT_DIR$/source/index.js" />
-      </list>
-    </option>
-  </component>
-  <component name="Vcs.Log.Tabs.Properties">
-    <option name="TAB_STATES">
-      <map>
-        <entry key="MAIN">
-          <value>
-            <State />
-          </value>
-        </entry>
-      </map>
-    </option>
-  </component>
-</project>
\ No newline at end of file
diff --git a/source/types.ts b/source/types.ts
index 30a1ec7..6246041 100644
--- a/source/types.ts
+++ b/source/types.ts
@@ -51,7 +51,7 @@ export interface ObservableLike {
 export type Falsy = false | 0 | 0n | '' | null | undefined;
 
 export interface WeakRef<T extends object> {
-	readonly [Symbol.toStringTag]: "WeakRef";
+	readonly [Symbol.toStringTag]: 'WeakRef';
 
 	/**
 	 * Returns the WeakRef instance's target object, or undefined if the target object has been