Well, the new version of vscode allows you to specify differently file type for the tabSize, here is the example of my settings.json with default 4 spaces and js/json 2 spaces:
{ "editor.fontSize": 20, "editor.tabSize": 4, "[javascript]": { "editor.tabSize": 2 }, "[json]": { "editor.tabSize": 2 } } PS: Well, if you do not know how to open this file: File / Preferences / Settings