feat(minifier): complete MangleIf (#8810)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>

Author: Boshen

crates/oxc_ast/src/ast_impl/js.rs

@@ -953,13 +953,15 @@ impl Statement<'_> {
     /// - `continue` => `true`
     /// - `if (true) { }` => `false`
     pub fn is_jump_statement(&self) -> bool {
-        matches!(
-            self,
-            Self::ReturnStatement(_)
-                | Self::ThrowStatement(_)
-                | Self::BreakStatement(_)
-                | Self::ContinueStatement(_)
-        )
+        self.get_one_child().is_some_and(|stmt| {
+            matches!(
+                stmt,
+                Self::ReturnStatement(_)
+                    | Self::ThrowStatement(_)
+                    | Self::BreakStatement(_)
+                    | Self::ContinueStatement(_)
+            )
+        })
     }
 
     /// Returns the single statement from block statement, or self

crates/oxc_minifier/src/peephole/minimize_conditions.rs

@@ -141,14 +141,19 @@ impl<'a> Traverse<'a> for PeepholeOptimizations {
         self.minimize_statements(stmts, ctx);
     }
 
-    fn exit_statement(&mut self, stmt: &mut Statement<'a>, ctx: &mut TraverseCtx<'a>) {
+    fn exit_statement(&mut self, stmt: &mut Statement<'a>, traverse_ctx: &mut TraverseCtx<'a>) {
         if !self.is_prev_function_changed() {
             return;
         }
-        let ctx = Ctx(ctx);
-        self.minimize_conditions_exit_statement(stmt, ctx);
-        self.remove_dead_code_exit_statement(stmt, ctx);
-        self.substitute_exit_statement(stmt, ctx);
+        Self::minimize_conditions_exit_statement(stmt, Ctx(traverse_ctx));
+        self.remove_dead_code_exit_statement(stmt, Ctx(traverse_ctx));
+        if let Statement::IfStatement(if_stmt) = stmt {
+            if let Some(folded_stmt) = self.try_minimize_if(if_stmt, traverse_ctx) {
+                *stmt = folded_stmt;
+                self.mark_current_function_as_changed();
+            }
+        }
+        self.substitute_exit_statement(stmt, Ctx(traverse_ctx));
     }
 
     fn exit_return_statement(&mut self, stmt: &mut ReturnStatement<'a>, ctx: &mut TraverseCtx<'a>) {

crates/oxc_minifier/src/peephole/mod.rs

@@ -177,19 +177,17 @@ impl<'a, 'b> PeepholeOptimizations {
             _ => {}
         }
 
-        // `if (test) {}` -> `test`
-        if if_stmt.alternate.is_none()
-            && match &if_stmt.consequent {
-                Statement::EmptyStatement(_) => true,
-                Statement::BlockStatement(s) => s.body.is_empty(),
-                _ => false,
-            }
-        {
-            let expr = ctx.ast.move_expression(&mut if_stmt.test);
-            return Some(ctx.ast.statement_expression(if_stmt.span, expr));
-        }
-
         if let Some(boolean) = ctx.get_side_free_boolean_value(&if_stmt.test) {
+            // Use "1" and "0" instead of "true" and "false" to be shorter.
+            // And also prevent swapping consequent and alternate when `!0` is encourtnered.
+            if let Expression::BooleanLiteral(b) = &if_stmt.test {
+                if_stmt.test = ctx.ast.expression_numeric_literal(
+                    b.span,
+                    if b.value { 1.0 } else { 0.0 },
+                    None,
+                    NumberBase::Decimal,
+                );
+            }
             let mut keep_var = KeepVar::new(ctx.ast);
             if boolean {
                 if let Some(alternate) = &if_stmt.alternate {

crates/oxc_minifier/src/peephole/remove_dead_code.rs

@@ -18,8 +18,7 @@ mod test {
     #[test]
     fn fold_block_into_if() {
         test("a;b;c;if(x){}", "a,b,c,x");
-        // FIXME: remove last `!`
-        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/src/peephole/statement_fusion.rs

@@ -60,7 +60,7 @@ fn dce_if_statement() {
     );
     test(
         "if (xxx) { foo } else if (false) { var a; var b; } else if (false) { var c; var d; }",
-        "if (xxx) foo; else if (false) var a, b; else if (false) var c, d;",
+        "if (xxx) foo; else if (0) var a, b; else if (0) var c, d;",
     );
 
     test("if (!false) { foo }", "foo");

crates/oxc_minifier/tests/peephole/dead_code_elimination.rs

@@ -16,23 +16,6 @@ fn test_same(source_text: &str) {
 
 #[test]
 fn integration() {
-    // FIXME
-    // test(
-    // "function writeInteger(int) {
-    // if (int >= 0)
-    // if (int <= 0xffffffff)
-    // return this.u32(int);
-    // else if (int > -0x80000000)
-    // return this.n32(int);
-    // }",
-    // "function writeInteger(int) {
-    // if (int >= 0) {
-    // if (int <= 4294967295) return this.u32(int);
-    // if (int > -2147483648) return this.n32(int);
-    // }
-    // }",
-    // );
-
     test(
         "require('./index.js')(function (e, os) {
     if (e) return console.log(e)
@@ -76,19 +59,6 @@ fn integration() {
         console.log(c, d);
         ",
     );
-
-    test(
-        "function _() {
-            if (currentChar === '\\n')
-                return pos + 1;
-            else if (currentChar !== ' ' && currentChar !== '\\t')
-                return pos + 1;
-        }",
-        "function _() {
-            if (currentChar === '\\n' || currentChar !== ' ' && currentChar !== '\\t')
-                return pos + 1;
-        }",
-    );
 }
 
 #[test]

crates/oxc_minifier/tests/peephole/mod.rs

@@ -7,21 +7,21 @@ Original   | minified   | minified   | gzip       | gzip       | Fixture
 
 287.63 kB  | 89.48 kB   | 90.07 kB   | 30.95 kB   | 31.95 kB   | jquery.js 
 
-342.15 kB  | 117.68 kB  | 118.14 kB  | 43.57 kB   | 44.37 kB   | vue.js    
+342.15 kB  | 117.68 kB  | 118.14 kB  | 43.56 kB   | 44.37 kB   | vue.js    
 
 544.10 kB  | 71.43 kB   | 72.48 kB   | 25.87 kB   | 26.20 kB   | lodash.js 
 
 555.77 kB  | 271.25 kB  | 270.13 kB  | 88.35 kB   | 90.80 kB   | d3.js     
 
-1.01 MB    | 440.96 kB  | 458.89 kB  | 122.50 kB  | 126.71 kB  | bundle.min.js
+1.01 MB    | 440.97 kB  | 458.89 kB  | 122.50 kB  | 126.71 kB  | bundle.min.js
 
 1.25 MB    | 650.36 kB  | 646.76 kB  | 161.01 kB  | 163.73 kB  | three.js  
 
-2.14 MB    | 718.61 kB  | 724.14 kB  | 162.13 kB  | 181.07 kB  | victory.js
+2.14 MB    | 718.69 kB  | 724.14 kB  | 162.15 kB  | 181.07 kB  | victory.js
 
-3.20 MB    | 1.01 MB    | 1.01 MB    | 324.31 kB  | 331.56 kB  | echarts.js
+3.20 MB    | 1.01 MB    | 1.01 MB    | 324.44 kB  | 331.56 kB  | echarts.js
 
-6.69 MB    | 2.30 MB    | 2.31 MB    | 468.52 kB  | 488.28 kB  | antd.js   
+6.69 MB    | 2.30 MB    | 2.31 MB    | 468.54 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.36 MB    | 3.49 MB    | 862.11 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.36 MB    | 3.49 MB    | 862.14 kB  | 915.50 kB  | typescript.js