diff --git a/packages/webpack-plugin/lib/wxss/runtime/api.js b/packages/webpack-plugin/lib/wxss/runtime/api.js
index 1da0a00359..ca90917e07 100644
--- a/packages/webpack-plugin/lib/wxss/runtime/api.js
+++ b/packages/webpack-plugin/lib/wxss/runtime/api.js
@@ -2,15 +2,15 @@
   MIT License http://www.opensource.org/licenses/mit-license.php
   Author Tobias Koppers @sokra
 */
-module.exports = (cssWithMappingToString) => {
+module.exports = function (cssWithMappingToString) {
   const list = []
 
   // return the list of modules as css string
   list.toString = function toString () {
-    return this.map((item) => {
-      let content = ''
+    return this.map(function (item) {
+      var content = ''
 
-      const needLayer = typeof item[5] !== 'undefined'
+      var needLayer = typeof item[5] !== 'undefined'
 
       if (item[4]) {
         content += `@supports (${item[4]}) {`
@@ -48,11 +48,11 @@ module.exports = (cssWithMappingToString) => {
       modules = [[null, modules, undefined]]
     }
 
-    const alreadyImportedModules = {}
+    var alreadyImportedModules = {}
 
     if (dedupe) {
       for (let k = 0; k < this.length; k++) {
-        const id = this[k][0]
+        var id = this[k][0]
 
         if (id != null) {
           alreadyImportedModules[id] = true
@@ -60,8 +60,8 @@ module.exports = (cssWithMappingToString) => {
       }
     }
 
-    for (let k = 0; k < modules.length; k++) {
-      const item = [].concat(modules[k])
+    for (var k = 0; k < modules.length; k++) {
+      var item = [].concat(modules[k])
 
       if (dedupe && alreadyImportedModules[item[0]]) {
         continue
diff --git a/packages/webpack-plugin/lib/wxss/runtime/noSourceMaps.js b/packages/webpack-plugin/lib/wxss/runtime/noSourceMaps.js
index 70a4131645..57b6c37fd7 100644
--- a/packages/webpack-plugin/lib/wxss/runtime/noSourceMaps.js
+++ b/packages/webpack-plugin/lib/wxss/runtime/noSourceMaps.js
@@ -1 +1,3 @@
-module.exports = (i) => i[1]
+module.exports = function (i) {
+  return i[1]
+}
diff --git a/packages/webpack-plugin/lib/wxss/runtime/sourceMaps.js b/packages/webpack-plugin/lib/wxss/runtime/sourceMaps.js
index e83b444c43..2de4696f87 100644
--- a/packages/webpack-plugin/lib/wxss/runtime/sourceMaps.js
+++ b/packages/webpack-plugin/lib/wxss/runtime/sourceMaps.js
@@ -1,6 +1,6 @@
-module.exports = (item) => {
-  const content = item[1]
-  const cssMapping = item[3]
+module.exports = function (item) {
+  var content = item[1]
+  var cssMapping = item[3]
 
   if (!cssMapping) {
     return content
@@ -8,13 +8,13 @@ module.exports = (item) => {
 
   if (typeof btoa === 'function') {
     // eslint-disable-next-line no-undef
-    const base64 = btoa(
+    var base64 = btoa(
       unescape(encodeURIComponent(JSON.stringify(cssMapping)))
     )
-    const data = `sourceMappingURL=data:application/json;charset=utf-8;base64,${base64}`
-    const sourceMapping = `/*# ${data} */`
+    var data = `sourceMappingURL=data:application/json;charset=utf-8;base64,${base64}`
+    var sourceMapping = `/*# ${data} */`
 
-    const sourceURLs = cssMapping.sources.map(
+    var sourceURLs = cssMapping.sources.map(
       (source) => `/*# sourceURL=${cssMapping.sourceRoot || ''}${source} */`
     )