From af65c3670f10bb59c852f329054af3c405bfa08e Mon Sep 17 00:00:00 2001
From: camc314 <18101008+camc314@users.noreply.github.com>
Date: Mon, 6 Jan 2025 23:26:20 +0000
Subject: [PATCH] feat(minifier): minimize double negated binary expressions
 (#8304)

---
 .../peephole_minimize_conditions.rs           | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs b/crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs
index 976a591db..c0afb4088 100644
--- a/crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs
+++ b/crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs
@@ -100,6 +100,23 @@ impl<'a> PeepholeMinimizeConditions {
                 if Self::is_in_boolean_context(ctx) {
                     return Some(ctx.ast.move_expression(&mut e1.argument));
                 }
+                if let Expression::BinaryExpression(bin_expr) = &e1.argument {
+                    if matches!(
+                        bin_expr.operator,
+                        BinaryOperator::Equality
+                            | BinaryOperator::Inequality
+                            | BinaryOperator::StrictEquality
+                            | BinaryOperator::StrictInequality
+                            | BinaryOperator::LessThan
+                            | BinaryOperator::LessEqualThan
+                            | BinaryOperator::GreaterThan
+                            | BinaryOperator::GreaterEqualThan
+                            | BinaryOperator::In
+                            | BinaryOperator::Instanceof
+                    ) {
+                        return Some(ctx.ast.move_expression(&mut e1.argument));
+                    }
+                }
             }
         }
 
@@ -1733,9 +1750,10 @@ mod test {
     }
 
     #[test]
-    fn minimize_nots_with_deletes() {
+    fn minimize_nots_with_binary_expressions() {
         test("!!delete x.y", "delete x.y");
         test("!!!delete x.y", "!delete x.y");
         test("!!!!delete x.y", "delete x.y");
+        test("var k = !!(foo instanceof bar)", "var k = foo instanceof bar");
     }
 }