feat: support named exports (#1087)

close #1080

Author: Jinjiang

lib/loader.js

@@ -273,8 +273,14 @@ module.exports = function (content) {
   if (script) {
     if (options.esModule) {
       output += script.src
-        ? getImportForImport('script', script)
-        : getImport('script', script) + '\n'
+        ? (
+            getNamedExportForImport('script', script) + '\n' +
+            getImportForImport('script', script)
+          )
+        : (
+            getNamedExport('script', script) + '\n' +
+            getImport('script', script)
+          ) + '\n'
     } else {
       output +=
         'var __vue_script__ = ' +
@@ -429,6 +435,7 @@ module.exports = function (content) {
         '  })\n'
       output += '})()}\n'
     }
+
     // final export
     if (options.esModule) {
       output += '\nexport default Component.exports\n'
@@ -461,6 +468,13 @@ module.exports = function (content) {
     )
   }
 
+  function getNamedExport (type, part, index, scoped) {
+    return (
+      'export * from ' +
+      getRequireString(type, part, index, scoped)
+    )
+  }
+
   function getRequireString (type, part, index, scoped) {
     return loaderUtils.stringifyRequest(
       loaderContext,
@@ -486,6 +500,13 @@ module.exports = function (content) {
     )
   }
 
+  function getNamedExportForImport (type, impt, scoped) {
+    return (
+      'export * from ' +
+      getRequireForImportString(type, impt, scoped)
+    )
+  }
+
   function getRequireForImportString (type, impt, scoped) {
     return loaderUtils.stringifyRequest(
       loaderContext,