fix(eslint-plugin): [no-unused-vars] handle logical assignment (#7854)

* fix(eslint-plugin): [no-unused-vars] handle logical assignment * refactor
typescript-eslint · Nov 1, 2023 · 11e57c5 · 11e57c5
1 parent c426884
commit 11e57c5
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diff --git a/packages/eslint-plugin/src/util/collectUnusedVariables.ts b/packages/eslint-plugin/src/util/collectUnusedVariables.ts
@@ -439,6 +439,8 @@ function isExported(variable: TSESLint.Scope.Variable): boolean {
   });
 }
 
+const LOGICAL_ASSIGNMENT_OPERATORS = new Set(['&&=', '||=', '??=']);
+
 /**
  * Determines if the variable is used.
  * @param variable The variable to check.
@@ -701,6 +703,7 @@ function isUsedVariable(variable: TSESLint.Scope.Variable): boolean {
       ref.isRead() && // in RHS of an assignment for itself. e.g. `a = a + 1`
       // self update. e.g. `a += 1`, `a++`
       ((parent.type === AST_NODE_TYPES.AssignmentExpression &&
+        !LOGICAL_ASSIGNMENT_OPERATORS.has(parent.operator) &&
         grandparent.type === AST_NODE_TYPES.ExpressionStatement &&
         parent.left === id) ||
         (parent.type === AST_NODE_TYPES.UpdateExpression &&

diff --git a/packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars.test.ts b/packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars.test.ts
@@ -1099,6 +1099,18 @@ interface Foo {
   bar: string;
 }
     `,
+    `
+let foo = 1;
+foo ??= 2;
+    `,
+    `
+let foo = 1;
+foo &&= 2;
+    `,
+    `
+let foo = 1;
+foo ||= 2;
+    `,
   ],
 
   invalid: [
@@ -1844,5 +1856,23 @@ const Foo = 'bar';
         },
       ],
     },
+    {
+      code: `
+let foo = 1;
+foo += 1;
+      `,
+      errors: [
+        {
+          messageId: 'unusedVar',
+          line: 3,
+          column: 1,
+          data: {
+            varName: 'foo',
+            action: 'assigned a value',
+            additional: '',
+          },
+        },
+      ],
+    },
   ],
 });