From 6afc590db8be48d65ead987446de6f9fdaf24fd6 Mon Sep 17 00:00:00 2001
From: camc314 <18101008+camc314@users.noreply.github.com>
Date: Mon, 6 Jan 2025 23:26:18 +0000
Subject: [PATCH] feat(minifier): compress typeof addition string (#8301)

---
 .../src/ast_passes/peephole_fold_constants.rs | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs b/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
index 29dc61ca5a25c..081d4826981f3 100644
--- a/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
+++ b/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
@@ -334,6 +334,18 @@ impl<'a, 'b> PeepholeFoldConstants {
                 }
             }
         }
+
+        // typeof foo + ""
+        if let Expression::UnaryExpression(left) = &e.left {
+            if left.operator.is_typeof() {
+                if let Expression::StringLiteral(right) = &e.right {
+                    if right.value.is_empty() {
+                        return Some(ctx.ast.move_expression(&mut e.left));
+                    }
+                }
+            }
+        }
+
         None
     }
 
@@ -1777,4 +1789,12 @@ mod test {
         test("true.toString()", "'true'");
         test("false.toString()", "'false'");
     }
+
+    #[test]
+    fn test_fold_typeof_addition_string() {
+        test_same("typeof foo");
+        test_same("typeof foo + '123'");
+        test("typeof foo + ''", "typeof foo");
+        test_same("typeof foo - ''");
+    }
 }