Slightly off topic, but you can chain your language selectors in VS Code settings so that:

    "[javascript]": {
        "editor.defaultFormatter": "esbenp.prettier-vscode"
    },
    "[typescript]": {
        "editor.defaultFormatter": "esbenp.prettier-vscode"
    },

Becomes:

    "[javascript][typescript]": {
        "editor.defaultFormatter": "esbenp.prettier-vscode"
    }