fix: make getRulesMetaForResults return a plain object in trivial case (#16438)

fasttime · web-flow · commit 325ad375a52d · 2022-10-18T22:46:44.000+02:00
diff --git a/lib/eslint/flat-eslint.js b/lib/eslint/flat-eslint.js
@@ -665,13 +665,12 @@ class FlatESLint {
      */
     getRulesMetaForResults(results) {
 
-        const resultRules = new Map();
-
         // short-circuit simple case
         if (results.length === 0) {
-            return resultRules;
+            return {};
         }
 
+        const resultRules = new Map();
         const { configs } = privateMembers.get(this);
 
         /*
diff --git a/tests/lib/eslint/eslint.js b/tests/lib/eslint/eslint.js
@@ -4971,7 +4971,7 @@ describe("ESLint", () => {
 
             const rulesMeta = engine.getRulesMetaForResults([]);
 
-            assert.strictEqual(Object.keys(rulesMeta).length, 0);
+            assert.deepStrictEqual(rulesMeta, {});
         });
 
         it("should return one rule meta when there is a linting error", async () => {
diff --git a/tests/lib/eslint/flat-eslint.js b/tests/lib/eslint/flat-eslint.js
@@ -3754,7 +3754,7 @@ describe("FlatESLint", () => {
 
             const rulesMeta = engine.getRulesMetaForResults([]);
 
-            assert.strictEqual(Object.keys(rulesMeta).length, 0);
+            assert.deepStrictEqual(rulesMeta, {});
         });
 
         it("should return one rule meta when there is a linting error", async () => {
