fix: no-unused-vars false positive with logical assignment operators (#17320)

gweesin · web-flow · commit a36bcb67f26b · 2023-06-30T12:37:14.000+02:00
* fix: no-unused-vars should be corrected in logical assignment operator Fixes #17299 * refactor: use astUtils.isLogicalAssignmentOperator check exception
diff --git a/lib/rules/no-unused-vars.js b/lib/rules/no-unused-vars.js
@@ -466,7 +466,8 @@ module.exports = {
                     (
                         parent.type === "AssignmentExpression" &&
                         parent.left === id &&
-                        isUnusedExpression(parent)
+                        isUnusedExpression(parent) &&
+                        !astUtils.isLogicalAssignmentOperator(parent.operator)
                     ) ||
                     (
                         parent.type === "UpdateExpression" &&
diff --git a/tests/lib/rules/no-unused-vars.js b/tests/lib/rules/no-unused-vars.js
@@ -417,6 +417,20 @@ ruleTester.run("no-unused-vars", rule, {
         {
             code: "import.meta",
             parserOptions: { ecmaVersion: 2020, sourceType: "module" }
+        },
+
+        // https://github.com/eslint/eslint/issues/17299
+        {
+            code: "var a; a ||= 1;",
+            parserOptions: { ecmaVersion: 2021 }
+        },
+        {
+            code: "var a; a &&= 1;",
+            parserOptions: { ecmaVersion: 2021 }
+        },
+        {
+            code: "var a; a ??= 1;",
+            parserOptions: { ecmaVersion: 2021 }
         }
     ],
     invalid: [

Original file line number	Diff line number	Diff line change
`@@ -466,7 +466,8 @@ module.exports = {`
`466`	`466`	`(`
`467`	`467`	`parent.type === "AssignmentExpression" &&`
`468`	`468`	`parent.left === id &&`
`469`		`- isUnusedExpression(parent)`
	`469`	`+ isUnusedExpression(parent) &&`
	`470`	`+ !astUtils.isLogicalAssignmentOperator(parent.operator)`
`470`	`471`	`) \|\|`
`471`	`472`	`(`
`472`	`473`	`parent.type === "UpdateExpression" &&`