JSHandle 类

🌐 JSHandle class

表示对 JavaScript 对象的引用。可以使用 Page.evaluateHandle() 创建实例。

🌐 Represents a reference to a JavaScript object. Instances can be created using Page.evaluateHandle().

句柄可以防止被引用的 JavaScript 对象被垃圾回收，除非该句柄被有意地释放。当其关联的框架被导航或父上下文被销毁时，JSHandles 会自动释放。

🌐 Handles prevent the referenced JavaScript object from being garbage-collected unless the handle is purposely disposed. JSHandles are auto-disposed when their associated frame is navigated away or the parent context gets destroyed.

句柄可以用作任何评估函数的参数，例如 Page.$eval()、Page.evaluate() 和 Page.evaluateHandle()。它们会被解析为其引用的对象。

🌐 Handles can be used as arguments for any evaluation function such as Page.$eval(), Page.evaluate(), and Page.evaluateHandle(). They are resolved to their referenced object.

语法

🌐 Signature

export declare abstract class JSHandle<T = unknown>

附注

🌐 Remarks

这个类的构造函数被标记为内部。第三方代码不应直接调用构造函数或创建继承 JSHandle 类的子类。

🌐 The constructor for this class is marked as internal. Third-party code should not call the constructor directly or create subclasses that extend the JSHandle class.

示例

🌐 Example

const windowHandle = await page.evaluateHandle(() => window);

属性

🌐 Properties

属性 🌐 Property	修饰符 🌐 Modifiers	类型 🌐 Type	描述 🌐 Description
_	optional	T	用于名义上对 JSHandle 进行类型定义。 🌐 Used for nominally typing JSHandle.
move		() => this

方法

🌐 Methods

方法 🌐 Method	修饰符 🌐 Modifiers	描述 🌐 Description
asElement()		如果 handle 是 ElementHandle 的实例，则为 null 或 handle 本身。 🌐 Either null or the handle itself if the handle is an instance of ElementHandle.
dispose()		释放句柄引用的对象以进行垃圾回收。 🌐 Releases the object referenced by the handle for garbage collection.
evaluate(pageFunction, args)		使用当前句柄作为第一个参数来计算给定函数。 🌐 Evaluates the given function with the current handle as its first argument.
evaluateHandle(pageFunction, args)		使用当前句柄作为第一个参数来计算给定函数。 🌐 Evaluates the given function with the current handle as its first argument.
getProperties()		获取表示当前句柄属性的句柄映射。 🌐 Gets a map of handles representing the properties of the current handle.
getProperty(propertyName)		从引用的对象中获取单个属性。 🌐 Fetches a single property from the referenced object.
getProperty(propertyName)
jsonValue()		表示引用对象的可序列化部分的普通对象。 🌐 A vanilla object representing the serializable portions of the referenced object. 附注 如果对象有一个 toJSON 函数，它不会被调用。 🌐 If the object has a toJSON function, it will not be called.
remoteObject()		提供对支撑此句柄的 Protocol.Runtime.RemoteObject 的访问。 🌐 Provides access to the Protocol.Runtime.RemoteObject backing this handle.
toString()		返回 JSHandle 的字符串表示形式。 🌐 Returns a string representation of the JSHandle. 附注 在调试过程中很有用。 🌐 Useful during debugging.