fix(webpack-cli): remove invalid stats warning with json flag

packages/webpack-cli/__tests__/StatsGroup.test.js

@@ -35,6 +35,7 @@ describe('StatsGroup', function () {
         ]);
 
         const result = group.run();
+        expect(result.options.stats).toBeFalsy();
         expect(result.outputOptions.json).toBeTruthy();
     });
 });

packages/webpack-cli/lib/groups/StatsGroup.js

@@ -19,7 +19,7 @@ class StatsGroup extends GroupHelper {
         } else {
             if (this.args.verbose) {
                 this.opts.options.stats = 'verbose';
-            } else if (!StatsGroup.validOptions().includes(this.args.stats)) {
+            } else if (this.args.stats && !StatsGroup.validOptions().includes(this.args.stats)) {
                 logger.warn(`'${this.args.stats}' is invalid value for stats. Using 'normal' option for stats`);
                 this.opts.options.stats = 'normal';
             } else {

test/json/json.test.js

@@ -12,4 +12,15 @@ describe('json flag', () => {
         // check the JSON is valid.
         expect(parseJson).not.toThrow();
     });
+
+    it('should return valid json with -j alias', () => {
+        const { stdout } = run(__dirname, ['-j']);
+
+        // helper function to check if JSON is valid
+        const parseJson = () => {
+            return JSON.parse(stdout);
+        };
+        // check the JSON is valid.
+        expect(parseJson).not.toThrow();
+    });
 });