I tried to avoid webpack since I knew compile time would be an issue for my other team members and it turned it out it was. As a web-dev I'm use to its workflow but onboarding game devs hate it. I have to hear everyday lets move to Godot, Unity, Unreal Engine because waiting 4 seconds for compiling is a headache.
Switching to Typescript is great for larger teams because it makes properties explicit. I personally like coffee-script and find it more productive if I'm the only dev but I swallowed the medicine on this one and it was worth it.
VSScode is powerful with Typescript but its not as productive as VIM. I think of code completion and seeing errors right away as crutches that atrophies a developers own skills to find code and errors but they can make it much easier for juniors and lower the bar, pair this with wallabyjs and you have a controlled environment that catches everything for you.
I found no resources on testing Phaser but figured out my own way of mocking Phaser objects, and came up with my own way to write acceptance-like tests for my game without electron.
I really wanted to contribute to Phaser3 and had put great effort to join but Richard was useless in responding. He said he was porting their tickets from Trello to Github and then I could contribute which never happened, I asked month over month. I really wanted to use Phaser 3 to future proof my game and I would have contributed significantly. I could have forked PhaserCE but its a mess which makes sense for the rewrite but working blindly on Phaser 3 would be futile. I am quite bitter about bitter about this because I 20 hours a week for 6 months I could have contribute and now I don't
I think I will likely just write my own lightweight game framework to map only what I need and gut Phaser. Even looking at Phaser 3 codebase with their big rewrite from scratch its still clunky and I think this is because they don't build games at a large scale with a team to have a good feeling to fine tune an engine.