chore: Modify watch script.

package.json

@@ -11,7 +11,7 @@
     "build": "node scripts/build.js && npm run doc && npm run lint",
     "watch": "node scripts/watch.js",
     "pretest": "npm run build",
-    "test": "jest --coverage",
+    "test": "jest --coverage --detectOpenHandles",
     "test:watch": "jest --watch",
     "doc": "cross-env PUBLIC_URL=. ENTRYDIR=website kkt build",
     "doc:dev": "cross-env PUBLIC_URL=. ENTRYDIR=website kkt start"

scripts/watch.js

@@ -13,6 +13,15 @@ const watchOptions = {
     commonjs(), // so Rollup can convert `ms` to an ES module
     babel({
       exclude: 'node_modules/**', // 只编译我们的源代码
+      presets: [[
+        '@babel/preset-env', {
+          /**
+           * Do not transpile typeof helper with itself
+           * https://github.com/babel/babel/pull/10788/files
+           */
+          exclude: ['@babel/plugin-transform-typeof-symbol'],
+        },
+      ]],
     }),
   ],
   output: [