First of all - thank you for an awesome tool. And second - I actually wanted to let you know, that I've built a small CLI tool for converting TMX files to JSONs - same as ones generated by JSON export from Tiled itself (and perfectly understandable by phaser.io), but with two features on top of it:
- it analyses used tiles and exports a single embedded optimised tileset with a single corresponding png file, containing only tiles used in a map
- in source TMX it correctly handles both embedded and external tilesets
These features allow creating a set of TSX files shared between different maps, while still making it possible to easily import them into phaser.io game engine. Also, this tool is deliberately made CLI for ease of use in CI/CD, but if you wish to have this implemented in JSON export in Tiled itself please let me know - maybe I'll be able to implement similar changes on your codebase as well, especially when given a little bit of guidance on where best to start.