chore: add more comments

tsconfig.json

@@ -7,10 +7,11 @@
     // This recommendation includes environments like Vitest, Vite Config File, Vite SSR, etc.
     "module": "ESNext",
 
+    // We expect users to use bundlers.
+    // So here we enable some resolution features that are only available in bundlers.
     "moduleResolution": "bundler",
     "resolveJsonModule": true,
     "allowImportingTsExtensions": true,
-    "useDefineForClassFields": true,
 
     // Required in Vue projects
     "jsx": "preserve",
@@ -35,8 +36,12 @@
     //   `build.target` option in the Vite config.
     //   So don't change the `target` field here. It has to be
     //   at least `ES2020` for dynamic `import()`s and `import.meta` to work correctly.
-    // - If you are not using Vite, feel free to override the `target` field.
+    // - If you are not using Vite, feel free to overwrite the `target` field.
     "target": "ESNext",
+    // For spec compilance.
+    // `true` by default if the `target` is `ES2020` or higher.
+    // Explicitly set it to `true` here in case some users want to overwrite the `target`.
+    "useDefineForClassFields": true,
 
     // Recommended
     "esModuleInterop": true,