All Scales should be extensible

[geo-developer]

From the website we have this:

Writing New Scale Types

Starting with Chart.js 2.0 scales can be individually extended. Scales should always derive from Chart.Scale.

So i assumed that every scale type you have should be extensible, but the only extensible ones are Scale and LinearScaleBase.

I don't really know if it is a bug or just as is, but if it is a bug you just have to change every scale you have apart from the LinearScaleBase, to instead of having the Scales as vars you need to add them to Chart namespace.

I got into this issue because i wanted to extend the TimeScale to change a function to fit my data, but i couldn't because it wasn't on Chart namespace, so i just copied the TimeScale you have in src/ to solve the problem.

Thanks and awesome library guys,
Pedro

[etimberg]

@geo-developer you can get the otger scales. The scaleService has a lookup function to get the constructor.

[geo-developer]

@etimberg thanks i'm going to check that.
Btw is it a bug or intended? Just asking because on docs you only show one way of extending.

Thanks again,
Pedro

[etimberg]

It's intended. When writing a custom scale, the scaleService is used to register the type. The lookup function is called getScaleConstructor(type) where type is the string type like 'linear' or 'time'

[geo-developer]

@etimberg Thanks again for the explanation, it works like a charm.

Maybe update docs in Writing New Scale Types to contain this option?
Just asking because in docs we can only see the extension of the base Scale.

Thanks again,
Pedro

[etimberg]

I believe this is fixed in #3751 as part of the new docs