feat(minifier): fold if(x)return;y -> if(!x)y (#8226)

oxc-project · Jan 3, 2025 · 2041477 · 2041477
1 parent 2f9fab9
commit 2041477
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Showing 5 changed files with 81 additions and 17 deletions.
diff --git a/crates/oxc_minifier/src/ast_passes/minimize_exit_points.rs b/crates/oxc_minifier/src/ast_passes/minimize_exit_points.rs
@@ -1,5 +1,7 @@
 use oxc_allocator::Vec;
 use oxc_ast::ast::*;
+use oxc_semantic::ScopeFlags;
+use oxc_span::{GetSpan, SPAN};
 use oxc_traverse::{traverse_mut_with_ctx, ReusableTraverseCtx, Traverse, TraverseCtx};
 
 use crate::CompressorPass;
@@ -14,20 +16,56 @@ pub struct MinimizeExitPoints {
 
 impl<'a> CompressorPass<'a> for MinimizeExitPoints {
     fn build(&mut self, program: &mut Program<'a>, ctx: &mut ReusableTraverseCtx<'a>) {
-        self.changed = true;
+        self.changed = false;
         traverse_mut_with_ctx(self, program, ctx);
     }
 }
 
 impl<'a> Traverse<'a> for MinimizeExitPoints {
-    fn exit_statements(&mut self, _stmts: &mut Vec<'a, Statement<'a>>, _ctx: &mut TraverseCtx<'a>) {
+    fn exit_statements(&mut self, stmts: &mut Vec<'a, Statement<'a>>, ctx: &mut TraverseCtx<'a>) {
+        self.fold_if_return(stmts, ctx);
     }
 }
 
-impl MinimizeExitPoints {
+impl<'a> MinimizeExitPoints {
     pub fn new() -> Self {
         Self { changed: false }
     }
+
+    // `if(x)return;foo` -> `if(!x)foo;`
+    fn fold_if_return(&mut self, stmts: &mut Vec<'a, Statement<'a>>, ctx: &mut TraverseCtx<'a>) {
+        if stmts.len() <= 1 {
+            return;
+        }
+        let Some(index) = stmts.iter().position(|stmt| {
+            if let Statement::IfStatement(if_stmt) = stmt {
+                if if_stmt.alternate.is_none()
+                    && matches!(
+                        if_stmt.consequent.get_one_child(),
+                        Some(Statement::ReturnStatement(s)) if s.argument.is_none()
+                    )
+                {
+                    return true;
+                }
+            }
+            false
+        }) else {
+            return;
+        };
+        let Some(stmts_rest) = stmts.get_mut(index + 1..) else { return };
+        let body = ctx.ast.vec_from_iter(stmts_rest.iter_mut().map(|s| ctx.ast.move_statement(s)));
+        let Statement::IfStatement(if_stmt) = &mut stmts[index] else { unreachable!() };
+        let scope_id = ctx.create_child_scope_of_current(ScopeFlags::empty());
+        let argument = ctx.ast.move_expression(&mut if_stmt.test);
+        if_stmt.test =
+            ctx.ast.expression_unary(argument.span(), UnaryOperator::LogicalNot, argument);
+        if_stmt.alternate = None;
+        if_stmt.consequent = Statement::BlockStatement(
+            ctx.ast.alloc_block_statement_with_scope_id(SPAN, body, scope_id),
+        );
+        stmts.retain(|stmt| !matches!(stmt, Statement::EmptyStatement(_)));
+        self.changed = true;
+    }
 }
 
 #[cfg(test)]
@@ -46,6 +84,20 @@ mod test {
         fold(source_text, source_text);
     }
 
+    #[test]
+    fn simple() {
+        fold(
+            "function foo() { if (foo) return; bar; quaz; }",
+            "function foo() { if (!foo) { bar; quaz; } }",
+        );
+        fold(
+            "function foo() { x; if (foo) return; bar; quaz; }",
+            "function foo() { x; if (!foo) { bar; quaz; } }",
+        );
+        fold_same("function foo() { if (foo) return }");
+        fold_same("function foo() { if (foo) return bar; baz }");
+    }
+
     #[test]
     #[ignore]
     fn test_break_optimization() {

diff --git a/crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs b/crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs
@@ -131,8 +131,11 @@ impl<'a> PeepholeMinimizeConditions {
                     {
                         if then_if_stmt.alternate.is_none() {
                             let and_left = ctx.ast.move_expression(&mut if_stmt.test);
+                            let Some(then_if_stmt) = if_stmt.consequent.get_one_child_mut() else {
+                                unreachable!()
+                            };
                             let Statement::IfStatement(mut then_if_stmt) =
-                                ctx.ast.move_statement(&mut if_stmt.consequent)
+                                ctx.ast.move_statement(then_if_stmt)
                             else {
                                 unreachable!()
                             };

diff --git a/crates/oxc_minifier/tests/ast_passes/mod.rs b/crates/oxc_minifier/tests/ast_passes/mod.rs
@@ -30,7 +30,7 @@ fn cjs() {
         });",
     );
     // @babel/types/lib/index.js
-    test_same(
+    test(
         r#"Object.keys(_index6).forEach(function(key) {
           if (key === "default" || key === "__esModule") return;
           if (Object.prototype.hasOwnProperty.call(_exportNames, key)) return;
@@ -42,6 +42,15 @@ fn cjs() {
             }
           });
         });"#,
+        "
+        Object.keys(_index6).forEach(function(key) {
+            !(key === 'default' || key === '__esModule') && !Object.prototype.hasOwnProperty.call(_exportNames, key) && (key in exports && exports[key] === _index6[key] || Object.defineProperty(exports, key, {
+                enumerable: !0,
+                get: function() {
+                    return _index6[key];
+                }
+            }));
+        });"
     );
 }
 

diff --git a/tasks/minsize/minsize.snap b/tasks/minsize/minsize.snap
@@ -1,27 +1,27 @@
            | Oxc        | ESBuild    | Oxc        | ESBuild    |
 Original   | minified   | minified   | gzip       | gzip       | Fixture
 -------------------------------------------------------------------------------------
-72.14 kB   | 23.71 kB   | 23.70 kB   | 8.62 kB    | 8.54 kB    | react.development.js
+72.14 kB   | 23.69 kB   | 23.70 kB   | 8.62 kB    | 8.54 kB    | react.development.js
 
-173.90 kB  | 59.90 kB   | 59.82 kB   | 19.43 kB   | 19.33 kB   | moment.js 
+173.90 kB  | 59.87 kB   | 59.82 kB   | 19.43 kB   | 19.33 kB   | moment.js 
 
-287.63 kB  | 90.37 kB   | 90.07 kB   | 32.10 kB   | 31.95 kB   | jquery.js 
+287.63 kB  | 90.27 kB   | 90.07 kB   | 32.09 kB   | 31.95 kB   | jquery.js 
 
-342.15 kB  | 118.47 kB  | 118.14 kB  | 44.54 kB   | 44.37 kB   | vue.js    
+342.15 kB  | 118.25 kB  | 118.14 kB  | 44.54 kB   | 44.37 kB   | vue.js    
 
-544.10 kB  | 71.84 kB   | 72.48 kB   | 26.19 kB   | 26.20 kB   | lodash.js 
+544.10 kB  | 71.81 kB   | 72.48 kB   | 26.18 kB   | 26.20 kB   | lodash.js 
 
-555.77 kB  | 273.58 kB  | 270.13 kB  | 90.98 kB   | 90.80 kB   | d3.js     
+555.77 kB  | 273.25 kB  | 270.13 kB  | 90.99 kB   | 90.80 kB   | d3.js     
 
-1.01 MB    | 460.75 kB  | 458.89 kB  | 126.88 kB  | 126.71 kB  | bundle.min.js
+1.01 MB    | 460.39 kB  | 458.89 kB  | 126.86 kB  | 126.71 kB  | bundle.min.js
 
-1.25 MB    | 653.16 kB  | 646.76 kB  | 163.57 kB  | 163.73 kB  | three.js  
+1.25 MB    | 652.71 kB  | 646.76 kB  | 163.55 kB  | 163.73 kB  | three.js  
 
-2.14 MB    | 726.69 kB  | 724.14 kB  | 180.25 kB  | 181.07 kB  | victory.js
+2.14 MB    | 726.39 kB  | 724.14 kB  | 180.23 kB  | 181.07 kB  | victory.js
 
 3.20 MB    | 1.01 MB    | 1.01 MB    | 332.13 kB  | 331.56 kB  | echarts.js
 
-6.69 MB    | 2.32 MB    | 2.31 MB    | 492.95 kB  | 488.28 kB  | antd.js   
+6.69 MB    | 2.32 MB    | 2.31 MB    | 492.88 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.51 MB    | 3.49 MB    | 910.02 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.50 MB    | 3.49 MB    | 910.01 kB  | 915.50 kB  | typescript.js
 
diff --git a/tasks/minsize/src/lib.rs b/tasks/minsize/src/lib.rs
@@ -145,7 +145,7 @@ fn minify(source_text: &str, source_type: SourceType) -> String {
     .build(symbols, scopes, &mut program);
     let ret = Minifier::new(MinifierOptions::default()).build(&allocator, &mut program);
     CodeGenerator::new()
-        .with_options(CodegenOptions { minify: true, ..CodegenOptions::default() })
+        .with_options(CodegenOptions { minify: true, comments: false, ..CodegenOptions::default() })
         .with_mangler(ret.mangler)
         .build(&program)
         .code