Fix TwoDimensionalPlotLine data type so the pointStyle member is not …

[jayatvitskiy]

…a union. Resolve #613

This is my first contribution to Webviz, so please let me know if I'm missing anything and/or if there's anything I should seek to do better in the future!

Summary

This is a very small pull request aimed to resolve issue #613.
As pointed out in the issue, the 2D Plot Template for Node Playground does not presently compile. This is because the return value is a TwoDimensionalPlot object. A TwoDimensionalPlot contains multiple TwoDimensionalPlotLine objects, which each have an optional member called pointStyle. Prior to my change, pointStyle was a union data type. The AST parser throws an error when we try to return an object that contains a union, so the template wasn't compiling.

I observed that there's no need for pointStyle to be a union type. In Typescript, a union type allows us to say pointStyle may be type X or type Y, but pointStyle is actually always a string. Thus, I simply changed each instance of pointStyle in the code so that instead of being a unique union data type, it would simply be a string.

In fact, I checked the GitHub blame feature for the relevant files and observed that pointStyle was actually previously a string (it was changed to a union 6 months ago, which is presumably what broke the template).

Test plan

I ran npm test to ensure that I didn't break anything. I observed that the current master branch does not actually pass all the tests, but my code passes the exact same number of tests as the master branch. Thus I concluded I did not break any tests.

I opened the 2D plot template. I no longer receive a compile error, and the template works as intended, so I believe I successfully addressed the issue in #613.

Next, I wrote a custom NodePlayground node that returns a TwoDimensionalPlot:

My goal here was to determine whether changing pointStyle to a string broke the intended functionality of pointStyle (i.e. am I still able to change the points on my plot to be stars, rectangles, etc). The above code resulted in a 2D plot with star indicators at (1,2) and (3,5) and a line between. I tested other point styles as well, such as "rect", and they worked correctly. Thus I concluded that the pointStyle functionality was working as intended.

Versioning impact

N/A

[lusuwen]

using code here, I receive a compile error "Unions are not allowed in return type." and i have no idea