build(@vant/lazyload): using rollup to bundle (#9598)

packages/vant-lazyload/package.json

@@ -14,20 +14,21 @@
     "types"
   ],
   "scripts": {
-    "dev": "babel src --out-dir dist/esm --watch",
-    "build": "babel src --out-dir dist/esm && BABEL_MODULE=commonjs babel src --out-dir dist/cjs",
+    "dev": "rollup --config rollup.config.js --watch",
+    "build": "rollup --config rollup.config.js",
     "release": "npm run build && release-it"
   },
   "license": "MIT",
   "repository": "https://github.com/youzan/vant/tree/dev/packages/vant-lazyload",
-  "devDependencies": {
-    "@babel/cli": "^7.12.8",
-    "@babel/core": "^7.12.9",
-    "release-it": "^14.2.2"
-  },
   "dependencies": {
     "@vant/use": "^1.3.2"
   },
+  "devDependencies": {
+    "@rollup/plugin-babel": "^5.2.1",
+    "@rollup/plugin-node-resolve": "^10.0.0",
+    "release-it": "^14.2.2",
+    "rollup": "^2.33.3"
+  },
   "release-it": {
     "git": {
       "tag": false,

packages/vant-lazyload/rollup.config.js

@@ -0,0 +1,22 @@
+import path from 'path';
+import babel from '@rollup/plugin-babel';
+import nodeResolve from '@rollup/plugin-node-resolve';
+
+export default {
+  input: path.join(__dirname, 'src', 'index.js'),
+  output: [
+    {
+      dir: 'dist/cjs',
+      format: 'cjs',
+    },
+    {
+      dir: 'dist/esm',
+      format: 'esm',
+    },
+  ],
+  external: ['vue', '@vant/use'],
+  plugins: [
+    babel({ babelHelpers: 'bundled', extensions: ['.js', '.ts'] }),
+    nodeResolve(),
+  ],
+};