History.back() behaves differently than documentation says.

[busslina]

Docs says:

The back() method of the History interface causes the browser to move back one page in the session history.

It has the same effect as calling . If there is no previous page, this method call does nothing.

This method is . Add a listener for the Window.popstate_event event in order to determine when the navigation has completed.

I'm testing the case where there isn't previous page and it is doing something: moving to root path.

Tested on Edge and Chrome.

Demo:

https://github.com/user-attachments/assets/a31abb93-15e7-4167-a19c-15bbd65158aa

[srujzs]

Looks like the docs are semi-malformed (missing asynchronous after "This method is "), but the MDN docs don't contain much more information. Is there a small repro you can share here? My only guess is that history is being modified somehow within the code.

The call to history.back() should correspond directly to JS' history.back(), so this is more of a discovery thing than anything actionable on the package's end.

[busslina]

Is there a small repro you can share here?

Not easy because I'm developping my own Flutter routing lib.

But I'm just calling that method:

@override
  SynchronousFuture<NavigationResult> flashBack() {
    if (!kIsWeb) {
      throw ('Only implemented for web');
    }

    web.window.history.back();
    return SynchronousFuture(const NavigationResult.success());
  }

[busslina]

And yeah, seems the doc error came from MDN. (If JavaScript is behaving equally, which I haven't tested yet).

[srujzs]

Not easy because I'm developping my own Flutter routing lib.

Gotcha. One option is to explore the history object before calling back, like determining if history.length is actually 1. Might also be worth looking at the generated code to see if we do anything weird besides directly call the JS API.

[busslina]

Thanks, I was worried to use that API as I tried to use the state object and it was a pain. But using length make it easy:

bool get canFlashBack => web.window.history.length >= 2;

[srujzs]

Great! I'm going to go ahead and close this for now since there's nothing actionable on package:web.