playwright.expect.expect_to_change

playwright.expect.expect_to_change(func, timeout_secs=10)

Context manager that yields when the value returned by func() changes.

Use this around code that has a side-effect of changing some state asynchronously (such as all browser actions), to prevent moving onto the next step of the test until this one has actually taken effect.

Parameters

func: Callable[[], Any]

A function that returns a value. The value returned by this function is compared to the value returned by subsequent calls to this function.

timeout_secs: float = 10

How long to wait for the value to change before raising TimeoutError.

Raises

Type	Description
TimeoutError	If the value does not change within timeout_secs.

Example

with expect_to_change(lambda: page.locator("#name").value()):
    page.keyboard.send_keys("hello")