The `Launcher` class was serving two purposes:
1. Launch browsers
2. Connect to browsers
Number 1) only needs to be done in Node land, but 2) is agnostic; in a
browser version of Puppeteer we'll need the ability to connect over a
websocket to send commands back and forth.
As part of the agnostification work we needed to split the `Launcher` up
so that the connection part can be made agnostic. Additionally, I
removed dependencies on `https`, `http` and `URL` from Node, instead
leaning on fetch (via `node-fetch` if in Node land) and the browser
`URL` API (which was added to Node in Node 10).
* chore: enforce file extensions on imports
To make our output agnostic it should include file extensions in the
output, as per the ESM spec. It's a bit odd for Node packages but makes
it easier to publish a browser build.
This CL migrates all the tests to TypeScript. The main benefits of this is that we start consuming our TypeScript definitions and therefore find errors in them. The act of migrating found some bugs in our definitions and now we can be sure to avoid them going forwards.
You'll notice the addition of some `TODO`s in the code; I didn't want this CL to get any bigger than it already is but I intend to follow those up once this lands. It's mostly figuring out how to extend the `expect` types with our `toBeGolden` helpers and some other slight confusions with types that the tests exposed.
Co-authored-by: Mathias Bynens <mathias@qiwi.be>
