Link latest documentation from old documentation

[not-my-profile]

Documentation Is:

• Missing or needed
• Confusing
• Not Sure?

Please Explain in Detail...

When I google for Chart.js documentation Google sometimes returns old documentation, which is particularly sneaky because Google hides the URL, for example:

leads to https://www.chartjs.org/docs/2.9.4/configuration/tooltip.html which doesn't at all say that this isn't the latest version.

Your Proposal for Changes

I think it would be nice to do something like the Rust docs.rs which displays when viewing out of date documentation.

[igorlukanin]

I think a couple of things can be done to mitigate this:

• update the dropdown menu with a stale versions warning
• add the robots.txt file

Stale version warning

We can show a visible warning for all numbered versions that will suggest checking the lastest version of the docs. IDK if a 5-word warning is too ugly—I think it might be okay since is should attract the attention.

We can also add a dedicated link to the latest version alongside the link to the development version.

I've submitted a PR with these changes: #10446

Please see how it works:

robots.txt file

We can add the robots.txt file to discourage Google from indexing all versions of the documentation pages except for the "latest" and "master".

It doesn't prevent these pages from being indexed completely—Google will still index them if there are any links to these pages (which is a good thing); however, this should remove most of the "stale" documentation pages from the index.

It will also remove the "most recent numeric version" pages from the index (as of this moment, it's https://www.chartjs.org/docs/3.8.0/); it seems to be okay since the same content is available as the "latest" versions (https://www.chartjs.org/docs/latest/).

I've submitted a PR with these changes: chartjs/www.chartjs.org#15

I've also tested them with a robots.txt checker. Please see screenshots:

• https://www.chartjs.org/ — allowed ✅
• https://www.chartjs.org/docs/ — allowed ✅
• https://www.chartjs.org/docs/latest/ — allowed ✅
• https://www.chartjs.org/docs/latest/getting-started/installation.html — allowed ✅
• https://www.chartjs.org/docs/3.8.0/ — disallowed ❌
• https://www.chartjs.org/docs/3.7.1/ — disallowed ❌

@etimberg @kurkle @LeeLenaleee @not-my-profile What do you think?