Package com.microsoft.playwright

Interface JSHandle

All Known Subinterfaces:
ElementHandle
All Known Implementing Classes:
ElementHandleImpl, JSHandleImpl
public interface JSHandle
JSHandle represents an in-page JavaScript object. JSHandles can be created with the Page.evaluateHandle() method. 

 JSHandle windowHandle = page.evaluateHandle("() => window");
 // ...

JSHandle prevents the referenced JavaScript object being garbage collected unless the handle is exposed with JSHandle.dispose(). JSHandles are auto-disposed when their origin frame gets navigated or the parent context gets destroyed.

JSHandle instances can be used as an argument in Page.evalOnSelector(), Page.evaluate() and Page.evaluateHandle() methods.

  • Method Details

    • asElement

      ElementHandle asElement()
      Returns either null or the object handle itself, if the object handle is an instance of ElementHandle.
      Since:
      v1.8

    • dispose

      void dispose()
      The jsHandle.dispose method stops referencing the element handle.
      Since:
      v1.8

    • evaluate

      default Object evaluate(String expression)
      Returns the return value of expression.

      This method passes this handle as the first argument to expression.

      If expression returns a Promise, then handle.evaluate would wait for the promise to resolve and return its value.

      **Usage** 

      
 ElementHandle tweetHandle = page.querySelector(".tweet .retweets");
 assertEquals("10 retweets", tweetHandle.evaluate("node => node.innerText"));
      Parameters:
      expression - JavaScript expression to be evaluated in the browser context. If the expression evaluates to a function, the function is automatically invoked.
      Since:
      v1.8

    • evaluate

      Object evaluate(String expression, Object arg)
      Returns the return value of expression.

      This method passes this handle as the first argument to expression.

      If expression returns a Promise, then handle.evaluate would wait for the promise to resolve and return its value.

      **Usage** 

      
 ElementHandle tweetHandle = page.querySelector(".tweet .retweets");
 assertEquals("10 retweets", tweetHandle.evaluate("node => node.innerText"));
      Parameters:
      expression - JavaScript expression to be evaluated in the browser context. If the expression evaluates to a function, the function is automatically invoked.
      arg - Optional argument to pass to expression.
      Since:
      v1.8

    • evaluateHandle

      default JSHandle evaluateHandle(String expression)
      Returns the return value of expression as a JSHandle.

      This method passes this handle as the first argument to expression.

      The only difference between jsHandle.evaluate and jsHandle.evaluateHandle is that jsHandle.evaluateHandle returns JSHandle.

      If the function passed to the jsHandle.evaluateHandle returns a Promise, then jsHandle.evaluateHandle would wait for the promise to resolve and return its value.

      See Page.evaluateHandle() for more details.

      Parameters:
      expression - JavaScript expression to be evaluated in the browser context. If the expression evaluates to a function, the function is automatically invoked.
      Since:
      v1.8

    • evaluateHandle

      JSHandle evaluateHandle(String expression, Object arg)
      Returns the return value of expression as a JSHandle.

      This method passes this handle as the first argument to expression.

      The only difference between jsHandle.evaluate and jsHandle.evaluateHandle is that jsHandle.evaluateHandle returns JSHandle.

      If the function passed to the jsHandle.evaluateHandle returns a Promise, then jsHandle.evaluateHandle would wait for the promise to resolve and return its value.

      See Page.evaluateHandle() for more details.

      Parameters:
      expression - JavaScript expression to be evaluated in the browser context. If the expression evaluates to a function, the function is automatically invoked.
      arg - Optional argument to pass to expression.
      Since:
      v1.8

    • getProperties

      Map<String,JSHandle> getProperties()
      The method returns a map with **own property names** as keys and JSHandle instances for the property values.

      **Usage** 

      
 JSHandle handle = page.evaluateHandle("() => ({ window, document })");
 Map<String, JSHandle> properties = handle.getProperties();
 JSHandle windowHandle = properties.get("window");
 JSHandle documentHandle = properties.get("document");
 handle.dispose();
      Since:
      v1.8

    • getProperty

      JSHandle getProperty(String propertyName)
      Fetches a single property from the referenced object.
      Parameters:
      propertyName - property to get
      Since:
      v1.8

    • jsonValue

      Object jsonValue()
      Returns a JSON representation of the object. If the object has a toJSON function, it **will not be called**.

      NOTE: The method will return an empty JSON object if the referenced object is not stringifiable. It will throw an error if the object has circular references.

      Since:
      v1.8