We have heard Google talk about two waves of indexing or crawling, espesially when it comes to processing JavaScript. But now Martin Splitt from Google says there is no such thing.
He did hint a while back that it is going away but now says there was really no such thing.
Martin said in a JavaScript SEO hangout at the 16:31 mark "First things first, there's no such thing as the second wave of crawling-ish." He added that by calling it that originally, it caused some issues. He said "The wave is an oversimplification that is coming back to us with interesting implications every now and then."
Here is the video embed where he said this:
So there you have it.
Forum discussion at YouTube Community.
Update: Some folks are doubting what Martin said, but Martin just commented on Facebook saying "It's all an oversimplification of what happens in the pipeline. There definitely isn't two waves of crawling. Indexing is a lovely can of worms, but yeah... not exactly two waves of indexing either."
Update 2: More questions answered on Twitter about this:
I'm not saying that there are implications on indexing, but it is more complex than two waves of indexing.
— Martin Splitt at 🏡🇨🇭 (@g33konaut) March 27, 2020
Also: SSR is beneficial for your users as well as bots that don't support JS and it's more robust, so the recommendation stands.
It is complicated. All I will say on this: Assume every page gets rendered. We *might* index or otherwise process the HTML before rendering.
— Martin Splitt at 🏡🇨🇭 (@g33konaut) March 27, 2020
I wrote that, I maintain that. It is up to date. You can also still use the two waves of indexing as a simplification for the process. It's just more complicated behind the scenes.
— Martin Splitt at 🏡🇨🇭 (@g33konaut) March 27, 2020
Right. That was specifically aimed at "two waves". That is an oversimplification. FWIW as a developer or SEO I would just assume my pages get rendered and get on with it :)
— Martin Splitt at 🏡🇨🇭 (@g33konaut) March 30, 2020
On a tangent: That doesn't mean that SSR isn't a good idea, but that's separate from all this anyway.