Fix: getErrorResults function to not mutate passed parameter (#11592)

* Chore: Changed getErrorResults to not alter passed `results` parameter * Chore: Added tests for getErrorResults Check that getErrorResults doesn't mutate passed argument
eslint · Apr 9, 2019 · b92ca6e · b92ca6e
1 parent ef7801e
commit b92ca6e
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/lib/cli-engine.js b/lib/cli-engine.js
@@ -543,13 +543,14 @@ class CLIEngine {
 
             if (filteredMessages.length > 0) {
                 filtered.push(
-                    Object.assign(result, {
+                    {
+                        ...result,
                         messages: filteredMessages,
                         errorCount: filteredMessages.length,
                         warningCount: 0,
                         fixableErrorCount: result.fixableErrorCount,
                         fixableWarningCount: 0
-                    })
+                    }
                 );
             }
         });

diff --git a/tests/lib/cli-engine.js b/tests/lib/cli-engine.js
@@ -3111,6 +3111,20 @@ describe("CLIEngine", () => {
             assert.strictEqual(errorResults[0].messages[4].severity, 2);
         });
 
+        it("should not mutate passed report.results parameter", () => {
+            process.chdir(originalDir);
+            const engine = new CLIEngine({
+                rules: { quotes: [1, "double"] }
+            });
+
+            const report = engine.executeOnText("var foo = 'bar';");
+            const reportResultsLength = report.results[0].messages.length;
+
+            CLIEngine.getErrorResults(report.results);
+
+            assert.lengthOf(report.results[0].messages, reportResultsLength);
+        });
+
         it("should report a warningCount of 0 when looking for errors only", () => {
 
             process.chdir(originalDir);