fix: treeshaking

[dangreen]

fixes #10163

Before (build of each export):

378 kB   Chart.js
378 kB   BarController.js
378 kB   BubbleController.js
378 kB   DoughnutController.js
378 kB   LineController.js
378 kB   PolarAreaController.js
378 kB   PieController.js
378 kB   RadarController.js
378 kB   ScatterController.js
378 kB   ArcElement.js
378 kB   LineElement.js
378 kB   PointElement.js
378 kB   BarElement.js
385 kB   Decimation.js
394 kB   Filler.js
397 kB   Legend.js
382 kB   SubTitle.js
382 kB   Title.js
384 kB   Tooltip.js
378 kB   CategoryScale.js
378 kB   LinearScale.js
378 kB   LogarithmicScale.js
378 kB   RadialLinearScale.js
378 kB   TimeScale.js
378 kB   TimeSeriesScale.js

After:

210 kB   Chart.js
83.7 kB  BarController.js
72.5 kB  BubbleController.js
80.2 kB  DoughnutController.js
74.1 kB  LineController.js
75.2 kB  PolarAreaController.js
80.4 kB  PieController.js
71.1 kB  RadarController.js
74.8 kB  ScatterController.js
40.4 kB  ArcElement.js
53.5 kB  LineElement.js
36 kB    PointElement.js
37 kB    BarElement.js
36.4 kB  Decimation.js
69.6 kB  Filler.js
71.1 kB  Legend.js
49.5 kB  SubTitle.js
49.6 kB  Title.js
85.8 kB  Tooltip.js
84.2 kB  CategoryScale.js
89.6 kB  LinearScale.js
92.6 kB  LogarithmicScale.js
106 kB   RadialLinearScale.js
95.4 kB  TimeScale.js
98.5 kB  TimeSeriesScale.js

Assign properties to classes is a side effect, so that's why tree-shaking didn't work. Changed it to static properties.

Also, some calls (class constructors) are marked as pure.

Also added size-limit to control sizes of specific exports. Action is failing cause it should be in the base branch to compare sizes.

[kurkle]

Using esbuild? I think most others can shake assigning class properties (it can have side effects, but usually does not). I'm not against changing to static properties, but its a breaking change.

[dangreen]

@kurkle webpack with terser (default minifier, actually terser make tree-shake). Why it's braking change ? Public API stays the same.

[kurkle]

Changing es version can break things.

[dangreen]

@kurkle we can add, for example, swc to transpilation

[dangreen]

my test bench: https://github.com/dangreen/chartjs-treeshaking-test

[dangreen]

@kurkle we can add, for example, swc to transpilation

swc and even babel transpile it to side-effected code 😕

[dangreen]

Using esbuild? I think most others can shake assigning class properties (it can have side effects, but usually does not)

terser/terser#724

babel/babel#5902

[dangreen]

@kurkle Ok, it's breaking change, but it's a desirable and valuable fix. So what is the release plan?

[kurkle]

I think this is one big thing to drive towards v4. I think we need to do 3.8.1 and 3.9 first. There has been some talk on moving to typescript in v4 (does not need to be full conversion IMO, just the transpilation stuff and some part as POC so things can be converted in steps). But this ts thing could pushed forward to v5 too.

[dangreen]

@kurkle Got it. Thank you!

[etimberg]

I'd be open to getting through 3.8.1 and 3.9 quickly so that we can start on v4 dev.

[kurkle]

Looks good to me. Needs a consensus we want to move to static fields. I'm game.

Need some note(s) to migration guide, as the defaults move up from prototype and someone might be using those.

Edit: also needs a rebase

[etimberg]

Will review this evening my time.

[benmccann]

Personally, I have no objection to using static properties. They look to be fairly well supported and users can use something like Babel if they need to support older browsers. So I'd be in favor of this change

[etimberg]

Overall looks good. Have one concern with the category scale change

[kurkle]

We need to merge these in some sane order to avoid tough rebases

[dangreen]

@benmccann

users can use something like Babel if they need to support older browsers

I have the article about that 🙂

https://dev.to/cubejs/why-and-how-to-transpile-dependencies-of-your-javascript-application-3phf

[dangreen]

@kurkle I think it will better to merge before #10525

[etimberg]

Going to merge this first, then #10525 can be rebased