Add support for loader sourceMap option and generate sourcemap from s…

…cratch when previous sourcemap is undefined

lib/index.js

@@ -5,7 +5,6 @@ const genId = require('./gen-id')
 
 const sourceMap = require('source-map')
 const SourceMapConsumer = sourceMap.SourceMapConsumer
-const SourceMapGenerator = sourceMap.SourceMapGenerator
 
 module.exports = function(contents, sourcemap) {
   const id = genId(this.resourcePath)
@@ -45,29 +44,33 @@ module.exports = function(contents, sourcemap) {
     }
   })
 
-  if (hasComponent) {
-    if (sourcemap) {
-      const generatedContents = genCode.generate(res, {
-        sourceMap: this.resourcePath,
-        sourceMapWithCode: true,
-        sourceContent: contents
-      })
+  if (!hasComponent) {
+    this.callback(null, contents, sourcemap)
+    return;
+  }
 
-      // apply the original sourcemap to the sourcemap generated by escodegen.
-      const sourceMapGenerator = generatedContents.map
+  if (this.sourceMap) {
+    const generatedContents = genCode.generate(res, {
+      sourceMap: this.resourcePath,
+      sourceMapWithCode: true,
+      sourceContent: contents
+    })
 
+    // apply the original sourcemap to the sourcemap generated by escodegen.
+    const sourceMapGenerator = generatedContents.map
+
+    if (sourcemap) {
       const originalSmc = new SourceMapConsumer(sourcemap)
       sourceMapGenerator.applySourceMap(originalSmc)
-      const outSourcemap = sourceMapGenerator.toJSON()
+    }
 
-      this.callback(null, generatedContents.code + genHotReload(id), outSourcemap)
-    } else {
-      const generatedContents = genCode.generate(res)
+    const outSourcemap = sourceMapGenerator.toJSON()
 
-      this.callback(null, generatedContents + genHotReload(id))
-    }
+    this.callback(null, generatedContents.code + genHotReload(id), outSourcemap)
   } else {
-    this.callback(null, contents, sourcemap)
+    const generatedContents = genCode.generate(res)
+
+    this.callback(null, generatedContents + genHotReload(id))
   }
 }