feat: respect user compiler / compilerOptions

Author: yyx990803

Diff for: lib/template-loader/index.js

@@ -67,24 +67,21 @@ function actuallyCompile (sourceTemplate, options, loaderContext, query) {
   const hasComment = query.comment != null
   const hasFunctionalTemplate = query.functional != null
 
-  const {
-    preserveWhitespace,
-    modules,
-    directives
-  } = options.compilerOptions || {}
+  const userCompilerOptions = options.compilerOptions || {}
 
-  const compilerOptions = {
+  const compilerOptions = Object.assign({}, userCompilerOptions, {
     scopeId: query.scoped != null ? `data-v-${id}` : null,
-    preserveWhitespace,
-    modules: defaultModules.concat(modules || []),
-    directives: directives || {},
+    modules: defaultModules.concat(userCompilerOptions.modules || []),
     comments: hasComment
-  }
+  })
+
+  // support user compiler
+  const compilerToUse = options.compiler || compiler
 
   const compile =
-    isServer && compiler.ssrCompile && options.optimizeSSR !== false
-      ? compiler.ssrCompile
-      : compiler.compile
+    isServer && compilerToUse.ssrCompile && options.optimizeSSR !== false
+      ? compilerToUse.ssrCompile
+      : compilerToUse.compile
 
   const compiled = compile(sourceTemplate, compilerOptions)