fix: errors from less (#401)

Author: alexander-akait

src/LessError.js

@@ -8,9 +8,11 @@ class LessError extends Error {
       "\n",
       ...LessError.getFileExcerptIfPossible(error),
       error.message.charAt(0).toUpperCase() + error.message.slice(1),
-      `      Error in ${path.normalize(error.filename)} (line ${
-        error.line
-      }, column ${error.column})`,
+      error.filename
+        ? `      Error in ${path.normalize(error.filename)} (line ${
+            error.line
+          }, column ${error.column})`
+        : "",
     ].join("\n");
 
     this.hideStack = true;

src/index.js

@@ -43,7 +43,7 @@ async function lessLoader(source) {
     result = await less.render(data, lessOptions);
   } catch (error) {
     if (error.filename) {
-      // `less` return forward slashes on windows when `webpack` resolver return an absolute windows path in `WebpackFileManager`
+      // `less` returns forward slashes on windows when `webpack` resolver return an absolute windows path in `WebpackFileManager`
       // Ref: https://github.com/webpack-contrib/less-loader/issues/357
       this.addDependency(path.normalize(error.filename));
     }