fix: output report generation

Author: grantcox

src/linter.js

@@ -152,12 +152,12 @@ function linter(key, options, compilation) {
         return;
       }
 
-      const content = outputReport.formatter;
-      (await loadFormatter(stylelint, outputReport.formatter))(
-        results,
-        returnValue,
-      );
-      formatter(results, returnValue);
+      const content = outputReport.formatter
+        ? (await loadFormatter(stylelint, outputReport.formatter))(
+            results,
+            returnValue,
+          )
+        : formatter(results, returnValue);
 
       let { filePath } = outputReport;
       if (!isAbsolute(filePath)) {

test/output-report.test.js

@@ -1,6 +1,6 @@
 import { join } from 'path';
 
-import { existsSync } from 'fs-extra';
+import { existsSync, readFileSync } from 'fs-extra';
 
 import pack from './utils/pack';
 
@@ -28,5 +28,8 @@ describe('output report', () => {
     expect(stats.hasWarnings()).toBe(false);
     expect(stats.hasErrors()).toBe(true);
     expect(existsSync(filePath)).toBe(true);
+    expect(JSON.parse(readFileSync(filePath, 'utf8'))).toMatchObject([
+      { source: expect.stringContaining('error/test.scss') },
+    ]);
   });
 });