listenBefore broken in v3.0.2

[pke]

Version

3.0.2

Steps to reproduce

Use a listenBefore and dispatch an action in that listener.
Have a componentWillReceiveProps that also dispatches an action.

Expected Behavior

In < 3.x.x the action sent by the listenBefore is emitted first, before the route transition and component update.

Actual Behavior

In 3.0.2 the action sent from listenBefore is dispatched only after the transition happened.

Using the exact same branch, just reverting back to 2.8.1 makes everything work again as expected.

[mjackson]

What changed between 2.8.1 and 3.0.2? Any idea?

I've spent all my time recently working on v4, and I don't plan on digging back into v3 any time soon. So if you can help us figure out what changed that's breaking your app and fix it, that'd be great.

[pke]

maybe it nothing in react-router but an update of the history package it uses internally?
Seems there was a change in #3647

[timdorr]

listenbefore comes directly from history. And the 3.x version of history is a rewrite from the previous 2.x version. Sounds like a history bug to me.

[mjackson]

Well, the history issue tracker is full of v3 bugs, most of which are being reported by people who are trying to use the router with history. If we stop using history v3 in the router, I bet nobody will care about those bugs anymore, because nobody will use history v3.

Can we update router v3 to just use history v4? All the same functionality should be there, and it seems like history v4 is fairly solid.

[mjackson]

Also, from #3647

This code isn't going to win any beauty awards.

😞

[ryanflorence]

History v3 does all that query parsing and stuff right? Would have to add that in.

[mjackson]

I'd recommend either downgrading to history 2.x or upgrading to history 4.x. It looks like history 3.x was just a bad release, done while I wasn't looking. My apologies for that, but I don't have the time to fix 3.x right now. By all accounts things are working perfectly in 4.x.

[pke]

However v4 doesn't support code splitting so elegantly anymore, does it?

[mjackson]

@pke The story for code splitting in v4 is far more elegant than anything we've done previously. The router is just components now, so you can code split like you would with any other components.

If you need an example, see how we're doing it on the router docs website.