The last time I tried, I used vue-cli to initialise the project and it “just worked” in that sense. Converting an existing JS app might be a bit trickier though - I guess you can specify at a per-component level what they’re implemented in via the script lang attribute. So basically I would go with: latest TypeScript, latest Yarn, latest Vue CLI, initialise a bank TS project, add some basic components to check everything works, move your old app components over one-by-one.