tsserver isn't LSP compliant, iirc they started with tsserver way before LSP was out, but since then didn't migrated to LSP. I think they didn't migrated becaus

tsserver isn't LSP compliant, iirc they started with tsserver way before LSP was out, but since then didn't migrated to LSP. I think they didn't migrated because: - It's a big selling point for vscode. - It might hard to migrate what they have to LSP, they might implement a lot of non LSP standards. - Migrate to LSP could possibly delay new features because of the rewrite in tsserver.