Add sourcemap consumption for accurate output

Author: jerrylow

index.js

@@ -1,12 +1,24 @@
 var checkCSS    = require('airtight-css-lint');
 var loaderUtils = require('loader-utils');
 var assign      = require("object-assign");
+var sourceMap   = require('source-map');
 
 function checkCSSLoader(source, options, webpack, map, callback) {
   var results = [];
 
   checkCSS(source, function (line, col, msg) {
-    results.push([ 'Line ' + line + ':' + col + ' - ' + msg ]);
+    var message = 'Line ' + line + ':' + col + ' - ' + msg;
+    if (map) {
+      var smc = new sourceMap.SourceMapConsumer(map);
+      var originalPos = smc.originalPositionFor({
+        line: line,
+        column: col
+      });
+
+      message = originalPos.source + ':' + originalPos.line + ':' + originalPos.column + ' - ' + msg;
+    }
+
+    results.push([message]);
   });
 
   if (results.length) {

package.json

@@ -12,6 +12,7 @@
   "dependencies": {
     "airtight-css-lint": "~0.3.1",
     "loader-utils": "^0.2.16",
-    "object-assign": "^4.1.1"
+    "object-assign": "^4.1.1",
+    "source-map": "^0.5.6"
   }
 }