NavigationPrecommitController: addHandler() method
The addHandler() method of the NavigationPrecommitController interface allows you to dynamically add a handler callback function in precommit code, which will then be run after the navigation has committed.
This is useful when the navigation workflow depends on information that is not know until precommit code has started running.
If the precommit and (post-commit) handler are independent, the handler can be specified in the in the options.handler argument passed to NavigateEvent.intercept().
Syntax
addHandler(handler);
Parameters
handler-
A callback function that defines the post-commit navigation handling behavior should be; it returns a promise.
The handler callback is invoked as though it was passed to the
NavigateEvent.intercept()method, and will run after thecurrentEntryproperty has been updated.
Return value
None (undefined).
Exceptions
InvalidStateErrorDOMException-
Thrown if:
- The originating
NavigateEventwas not intercepted or has been canceled. - The
Documentis not fully active.
- The originating
SecurityErrorDOMException-
Thrown if the event
isTrustedattribute isfalse.
Examples
For more examples see NavigationPrecommitController.
Basic usage
This example shows a precommitHandler implementation that fetches data for a page and uses addHandler() to add different handlers based on the page type (the implementations of the fetchConfig, setupVideoPlayer() and setupArticleView() are not given).
navigation.addEventListener("navigate", (event) => {
event.intercept({
async precommitHandler(controller) {
const pageData = await fetchConfig();
if (pageData.type === "video") {
controller.addHandler(() => setupVideoPlayer());
} else {
controller.addHandler(() => setupArticleView());
}
},
});
});
Specifications
| Specification |
|---|
| HTML # dom-navigationprecommitcontroller-addhandler |