Does anybody know how to translate Javascript to Typescript?

Re: Does anybody know how to translate Javascript to Typescript?

AFAIK there's no magical tool [nor formula...] allowing you to really sort of "reverse back the engine process".
That is, converting JavaScript transpilled code result back to it's original TypeScript state.

First you have to consider the fact that TypeScript is a superset of JavaScript, which means that the original code
you would write in TypeScript is meant to be transpiled in JavaScript and NOT the other way around.

You could of course try modifying the .js extension to .ts  -as pointed in the link - and then refactor code manually piece-by-piece. Personally I would rather suggest investing some time learning TypeScript as it will be much more rewarding option in the end.

RE: d3js-orgchart
That's an interesting sample which may worth taking a look at. The code uses php getPositions.php function to generate json but that's okay as result... I used a mock json and came with similar result.

To be honnest, I haven't really found much existing custom components that actually come near to what you're looking for unfortunately.  

You can take a look at this one TreeViz

One which I found real nice and interesting was the Breakdown Tree sample built during a contest.

However it seems the author thought the coding approach was a bit deprecated and no longer met new PBI Visuals criterias. So he has decided to remove content from Github. :smileysad:
Same thing for another one shown in following  Decomposition Tree video.  Link is broken :smileysad:
Authors could have given access so we could have a peak under the hood. Who jnows we may have come with something where they left off... Anyway...

So in conclusion, when dealing with creating custom Tree viz this leaves us 3 options:

1st option -would be to create a new custom component "all from scratch" from the ground up in order to recreate a similar code logic in TypeScript.
That may not be a profitable options unless of course you're confortable and proficient enough in combining TypeScript and d3.js.

2nd option - would be taking an existing raw d3.js code and bring modification in order to adapt it to a Power BI Visuals context.
Jon Gallant gave a good liquidFillGauge example  on How to Create a Power BI Custom Visual Based on an Existing d3 Visual 3 part series. That's a basic single data approach. Taking an existing Tree Viz raw d3.js code would avoid you writing everything from the ground up though hierarchic dataViewMapping and conversion wiring may still require a bit more work... 

3rd options - is to use Visio pre-built orgchart tool. That may not be the best option as it's still in preview and will request
hosting the Visio file either on OneDrive Business or on Sharepoint Server but still it's better than nothing.