feat(minifier): minimize !(a, b) -> a, !b (#8746)

Author: Boshen

crates/oxc_minifier/src/peephole/minimize_conditions.rs

@@ -128,6 +128,7 @@ impl<'a> PeepholeOptimizations {
             .unwrap_or_else(|| Expression::UnaryExpression(ctx.ast.alloc(unary)))
     }
 
+    /// `MaybeSimplifyNot`: <https://github.com/evanw/esbuild/blob/v0.24.2/internal/js_ast/js_ast_helpers.go#L73>
     fn try_minimize_not(
         expr: &mut UnaryExpression<'a>,
         ctx: Ctx<'a, '_>,
@@ -136,15 +137,22 @@ impl<'a> PeepholeOptimizations {
             return None;
         }
         match &mut expr.argument {
+            // `!!true` -> `true`
+            // `!!false` -> `false`
             Expression::UnaryExpression(e)
                 if e.operator.is_not() && ValueType::from(&e.argument).is_boolean() =>
             {
                 Some(ctx.ast.move_expression(&mut e.argument))
             }
+            // `!(a == b)` => `a != b`
+            // `!(a != b)` => `a == b`
+            // `!(a === b)` => `a !== b`
+            // `!(a !== b)` => `a === b`
             Expression::BinaryExpression(e) if e.operator.is_equality() => {
                 e.operator = e.operator.equality_inverse_operator().unwrap();
                 Some(ctx.ast.move_expression(&mut expr.argument))
             }
+            // `!(a == b ? foo: bar)` => `a != b ? foo : bar`
             Expression::ConditionalExpression(conditional_expr) => {
                 if let Expression::BinaryExpression(e) = &mut conditional_expr.test {
                     if e.operator.is_equality() {
@@ -154,6 +162,17 @@ impl<'a> PeepholeOptimizations {
                 }
                 None
             }
+            // "!(a, b)" => "a, !b"
+            Expression::SequenceExpression(sequence_expr) => {
+                if let Some(e) = sequence_expr.expressions.pop() {
+                    let e = ctx.ast.expression_unary(e.span(), UnaryOperator::LogicalNot, e);
+                    let expressions = ctx.ast.vec_from_iter(
+                        sequence_expr.expressions.drain(..).chain(std::iter::once(e)),
+                    );
+                    return Some(ctx.ast.expression_sequence(sequence_expr.span, expressions));
+                }
+                None
+            }
             _ => None,
         }
     }
@@ -2310,6 +2329,7 @@ mod test {
         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");
+        test("!(a, b)", "a, !b");
     }
 
     #[test]

crates/oxc_minifier/src/peephole/statement_fusion.rs

@@ -201,7 +201,7 @@ mod test {
     #[test]
     fn fold_block_into_if() {
         test("a;b;c;if(x){}", "a,b,c,x");
-        test("a;b;c;if(x,y){}else{}", "a, b, c, !(x, y);");
+        test("a;b;c;if(x,y){}else{}", "a, b, c, x, !y;");
         test("a;b;c;if(x,y){}", "a, b, c, x, y");
         test("a;b;c;if(x,y,z){}", "a, b, c, x, y, z");
         test("a();if(a()){}a()", "a(), a(), a()");

crates/oxc_minifier/tests/peephole/mod.rs

@@ -82,7 +82,7 @@ fn integration() {
          }
          console.log(c, d);
         ",
-        "if (!((() => console.log('effect'))(), !0)) for (var c = 1, c; unknownGlobal; unknownGlobal && !0) var d;
+        "if ((() => console.log('effect'))(), !1) for (var c = 1, c; unknownGlobal; unknownGlobal && !0) var d;
         console.log(c, d);
         ",
     );

tasks/minsize/minsize.snap

@@ -23,5 +23,5 @@ Original   | minified   | minified   | gzip       | gzip       | Fixture
 
 6.69 MB    | 2.30 MB    | 2.31 MB    | 470.00 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.37 MB    | 3.49 MB    | 866.66 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.37 MB    | 3.49 MB    | 866.64 kB  | 915.50 kB  | typescript.js