Remove xssi trap from sourcemaps as Firefox doesn't support it.

[ci skip]

README.md

@@ -164,7 +164,7 @@ For most projects, it is better to configure `language-babel` via project-based
   ```
 
 * #### Create Map
-  If transpiled output is being saved a separate source map can be also be saved. The source file name will be used with a new suffix of `.js.map` and sent to a directory specified in `Babel Maps Path`. To avoid any possible XSSI issues the map file is prefixed with `)]}`
+  If transpiled output is being saved a separate source map can be also be saved. The source file name will be used with a new suffix of `.js.map` and sent to a directory specified in `Babel Maps Path`.
 
   If `.babelrc` files use the `sourceMaps: inline` or `sourceMaps both` option, turn this `createMap` option off as the map data is stored as part of the source file.
 

lib/transpiler.coffee

@@ -228,9 +228,8 @@ class Transpiler
               file: f
               names: msgRet.result.map.names
               mappings: msgRet.result.map.mappings
-            xssiProtection = ')]}\n'
-            fs.writeFileSync pathTo.mapFile,
-              xssiProtection + JSON.stringify mapJson, null, ' '
+            #xssiProtection = ')]}\n'    # removed this line as Firefox doesn't support removal of xssi prefix!
+            fs.writeFileSync pathTo.mapFile, JSON.stringify mapJson, null, ' '
 
   # clean notification messages
   cleanNotifications: (pathTo) ->
@@ -391,7 +390,7 @@ class Transpiler
 
     sourceFileName = parsedSourceFile.name  + fnExt
     mapFileName = parsedSourceFile.name  + fnExt + '.map'
-    
+
     absTranspiledFile = path.normalize(path.join(absTranspileRoot, relSourceRootToSourceFile , sourceFileName ))
     absMapFile = path.normalize(path.join(absMapsRoot, relSourceRootToSourceFile, mapFileName ))