Intent to Ship: Navigation API: add post-commit handler from precommit

[Chromestatus]

Contact emails

nrose...@chromium.org

Explainer

https://github.com/WICG/navigation-api/pull/294

Specification

https://html.spec.whatwg.org/#dom-navigationprecommitcontroller-addhandler

Summary

Currently when intercepting navigations with the `navigate` event, precommitHandlers and post-commit ordinary handlers are passed separately. This works well when there is only one or the other, but can be a bit clunky when the flow includes a precommitHandler that leads to a post-commit handler. This addition is a small ergonomic improvement that enables registering a post-commit handler while invoking a precommit handler.

Blink component

Blink>DOM

Web Feature ID

navigation

Motivation

This is a small ergonomic fix to the API enabling a bit more flexibility.

Initial public proposal

https://github.com/whatwg/html/issues/11956

TAG review

No information provided

TAG review status

Pending

Risks

Interoperability and Compatibility

None, new API

Gecko: No signal

WebKit: No signal

Web developers: Positive This was initially raised by Jake Archibald when at Shopify.

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

No information provided

Debuggability

No information provided

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

Yes

Flag name on about://flags

No information provided

Finch feature name

NavigateEventAddHandlerOnPrecommit

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/465487215

Estimated milestones

Shipping on desktop	147
Shipping on Android	147
Shipping on WebView	147

Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).

No information provided

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5176907844943872?gate=6492610946531328

This intent message was generated by Chrome Platform Status.

[Yoav Weiss (@Shopify)]

On Tuesday, February 3, 2026 at 1:36:06 PM UTC+1 Chromestatus wrote:

Contact emails

nrose...@chromium.org

Explainer

https://github.com/WICG/navigation-api/pull/294

A bit more details would be useful here.
Even reading through https://github.com/WICG/navigation-api?tab=readme-ov-file#precommit-handlers, the role of post-commit handlers, nor how does one define them today is not clear.

I *think* I have a vague idea, so let me try to take a stab and let me know if I got it right.
Currently a developer that wants to add a post-commit handler (or simply a `handler` in the current API) to e.g. send analytics that a navigation has happened, can do that using
```
navigation.addEventListener("navigate", e => {
   if (e.canIntercept) {
    const handler = sendAnalytics(e);
    e.intercept({ handler });
  }
});
```

When they want to do something pre-commit (e.g. cancel the navigation if the target URL doesn't lead to a cat video), they can do something like

```
navigation.addEventListener("navigate", e => {
   if (e.canIntercept) {
    const precommitHandler = verifyCatVideo(controller);
    e.intercept({ precommitHandler });
  }
});
```
They can even add both.

But when developers today want to add a post-commit (or "regular") handler as a result of some handler in the pre-commit, they have no way of doing that.

This proposal is to add an `addHandler` method to the precommit controller, that would enable to add such post-commit handlers.

Is that roughly accurate?

If so, what would be an example use-case of wanting to add a post-commit handler as a result of pre-commit logic? What information does the pre-commit handler have that a post-commit logic doesn't?

[Noam Rosenthal]

Yes!

> If so, what would be an example use-case of wanting to add a post-commit handler as a result of pre-commit logic? What information does the pre-commit handler have that a post-commit logic doesn't?

Something like this, where the precommit handler performs some logic
to understand what to do with the request, and perhaps begins some
sort of shell, to be later populated by the handler:
```js

navigation.addEventListener("navigate", e => {
if (e.canIntercept) {

e.intercept({
async precommitHandler(controller) {
if (should_redirect(e.destination.url)) [
e.redirect(new_url);
return;
}
else if (should_cancel(destination.url)) {
throw new Error("cancel this navigation");
}
const contentPromise = fetchPageData();
const shell = await fetchPageShell();

shell.show_skeleton();

controller.addHandler(() => show_actual_data(await contentPromise));
}
}
});
```

Doing it this way is slightly more ergonomic than managing promises
outside of the intercept call.
See https://github.com/WICG/navigation-api/issues/66#issuecomment-1199002825
for old discussion about this.

[Yoav Weiss (@Shopify)]

LGTM1

[Alex Russell]

LGTM2

[Vladimir Levin]

Hey,

Can you please file signals for other browser vendors?

Thanks!

Vlad

[Noam Rosenthal]

On Wed, Feb 4, 2026 at 4:22 PM Vladimir Levin <vmp...@chromium.org> wrote:
>
> Hey,
>
> Can you please file signals for other browser vendors?
>
> Thanks!
> Vlad

Aye. Updated the chromestatus.
Mozilla apparently has already implemented this as part of their
initial support for precommitHandler.
Webkit: https://github.com/WebKit/standards-positions/issues/612

[Philip Jägenstedt]

LGTM3

--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+...@chromium.org.
To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAJn%3DMYZwBNgP_Kq-djzLjSTjJX%3DVuZco1SN6w4JPGiMB2bq_xQ%40mail.gmail.com.