diff --git a/packages/webpack-plugin/lib/platform/index.js b/packages/webpack-plugin/lib/platform/index.js
index 3553a1f59b..0f3aa77b71 100644
--- a/packages/webpack-plugin/lib/platform/index.js
+++ b/packages/webpack-plugin/lib/platform/index.js
@@ -1,12 +1,4 @@
 const runRules = require('./run-rules')
-const specMap = {
-  template: {
-    wx: require('./template/wx')
-  },
-  json: {
-    wx: require('./json/wx')
-  }
-}
 
 module.exports = function getRulesRunner ({
   type,
@@ -20,7 +12,15 @@ module.exports = function getRulesRunner ({
   warn,
   error
 }) {
-  const spec = specMap[type] && specMap[type][srcMode] && specMap[type][srcMode]({ warn, error })
+  const specMap = {
+    template: {
+      wx: require('./template/wx')
+    },
+    json: {
+      wx: require('./json/wx')
+    }
+  }
+  const spec = specMap[type]?.[srcMode]?.({ warn, error })
   if (spec && spec.supportedModes.indexOf(mode) > -1) {
     const normalizeTest = spec.normalizeTest
     const mainRules = mainKey ? spec[mainKey] : spec