I get that Flash hit a sweet spot. I'm not sure I get why nothing has really replaced it. There are other apps that give you animated vector graphics, in an IDE, with coding.
Here's 2?
https://cavalry.scenegroup.co/
I believe Unity doesn't do flash style vector animations. It will take in SVGs, turn them into meshes and apply skeletons. That said, it has replaced Flash in turns of the 1000s and 1000s of web games made with it.
https://itch.io/games/platform-web (majorty are Unity?)
Fun history: There was a flash like (vector animation program) for the Apple II called Fantavision.
https://youtu.be/8_Bm8bidrpE?t=40
It would export executables IIRC.
I tried Rive Editor and I could not export my animation unless I upgraded to a paid plan, not even to a proprietary format. The free plan is is just a demo with no real world usage, not even for hobby.
A bit mad because I spent more time playing with it than I would like to admit
Rive looks pretty nice, but a subscription pricing model without any option for offline use for an authoring tool like that is very unappealing to me.
Rive has an open SDK and my understanding is that you could build an entire app without ever opening theirs. But then there goes the “flash” vibe, unfortunately. Their primitives are also a little obscure without their IDE.
All of those alternatives fail at debugging, because to this day browser teams don't consider 2D and 3D debugging tools something worthwhile having on developer tooling.
So in some cases you need a native build to try to replicate browser issues, and then being able to plug into RenderDoc, Instruments, PIX,....
Flash had the tools.
Safari's devtools has a visual <canvas> debugger. I remember using it, seeing all the CanvasRenderingContext2D calls that affected the canvas listed, and scrubbing left and right through time to see how a frame was built up.
Thanks for the heads up, at least that is something.