feat(minifier): optional catch binding when catch param is unused

crates/oxc_minifier/src/ast_passes/mod.rs

@@ -50,7 +50,7 @@ pub struct PeepholeOptimizations {
 }
 
 impl PeepholeOptimizations {
-    pub fn new(in_fixed_loop: bool, options: CompressOptions) -> Self {
+    pub fn new(in_fixed_loop: bool, _options: CompressOptions) -> Self {
         Self {
             x0_statement_fusion: StatementFusion::new(),
             x1_minimize_exit_points: MinimizeExitPoints::new(),
@@ -59,7 +59,6 @@ impl PeepholeOptimizations {
             x4_peephole_remove_dead_code: PeepholeRemoveDeadCode::new(),
             x5_peephole_minimize_conditions: PeepholeMinimizeConditions::new(in_fixed_loop),
             x6_peephole_substitute_alternate_syntax: PeepholeSubstituteAlternateSyntax::new(
-                options,
                 in_fixed_loop,
             ),
             x7_peephole_replace_known_methods: PeepholeReplaceKnownMethods::new(),
@@ -185,10 +184,6 @@ impl<'a> Traverse<'a> for PeepholeOptimizations {
     ) {
         self.x9_convert_to_dotted_properties.exit_member_expression(expr, ctx);
     }
-
-    fn exit_catch_clause(&mut self, catch: &mut CatchClause<'a>, ctx: &mut TraverseCtx<'a>) {
-        self.x6_peephole_substitute_alternate_syntax.exit_catch_clause(catch, ctx);
-    }
 }
 
 pub struct DeadCodeElimination {

crates/oxc_minifier/src/ast_passes/peephole_substitute_alternate_syntax.rs

@@ -4,20 +4,18 @@ use oxc_ecmascript::{ToInt32, ToJsString};
 use oxc_semantic::IsGlobalReference;
 use oxc_span::{GetSpan, SPAN};
 use oxc_syntax::{
-    es_target::ESTarget,
     number::NumberBase,
     operator::{BinaryOperator, UnaryOperator},
 };
 use oxc_traverse::{traverse_mut_with_ctx, Ancestor, ReusableTraverseCtx, Traverse, TraverseCtx};
 
-use crate::{node_util::Ctx, CompressOptions, CompressorPass};
+use crate::{node_util::Ctx, CompressorPass};
 
 /// A peephole optimization that minimizes code by simplifying conditional
 /// expressions, replacing IFs with HOOKs, replacing object constructors
 /// with literals, and simplifying returns.
 /// <https://github.com/google/closure-compiler/blob/v20240609/src/com/google/javascript/jscomp/PeepholeSubstituteAlternateSyntax.java>
 pub struct PeepholeSubstituteAlternateSyntax {
-    options: CompressOptions,
     /// Do not compress syntaxes that are hard to analyze inside the fixed loop.
     /// e.g. Do not compress `undefined -> void 0`, `true` -> `!0`.
     /// Opposite of `late` in Closure Compiler.
@@ -46,10 +44,6 @@ impl<'a> Traverse<'a> for PeepholeSubstituteAlternateSyntax {
         self.compress_return_statement(stmt);
     }
 
-    fn exit_catch_clause(&mut self, catch: &mut CatchClause<'a>, _ctx: &mut TraverseCtx<'a>) {
-        self.compress_catch_clause(catch);
-    }
-
     fn exit_variable_declaration(
         &mut self,
         decl: &mut VariableDeclaration<'a>,
@@ -116,8 +110,8 @@ impl<'a> Traverse<'a> for PeepholeSubstituteAlternateSyntax {
 }
 
 impl<'a, 'b> PeepholeSubstituteAlternateSyntax {
-    pub fn new(options: CompressOptions, in_fixed_loop: bool) -> Self {
-        Self { options, in_fixed_loop, in_define_export: false, changed: false }
+    pub fn new(in_fixed_loop: bool) -> Self {
+        Self { in_fixed_loop, in_define_export: false, changed: false }
     }
 
     /// Test `Object.defineProperty(exports, ...)`
@@ -691,33 +685,18 @@ impl<'a, 'b> PeepholeSubstituteAlternateSyntax {
     fn empty_array_literal(ctx: Ctx<'a, 'b>) -> Expression<'a> {
         Self::array_literal(ctx.ast.vec(), ctx)
     }
-
-    fn compress_catch_clause(&mut self, catch: &mut CatchClause<'a>) {
-        if catch.body.body.is_empty()
-            && !self.in_fixed_loop
-            && self.options.target >= ESTarget::ES2019
-        {
-            if let Some(param) = &catch.param {
-                if param.pattern.kind.is_binding_identifier() {
-                    catch.param = None;
-                    self.changed = true;
-                }
-            };
-        }
-    }
 }
 
 /// Port from <https://github.com/google/closure-compiler/blob/v20240609/test/com/google/javascript/jscomp/PeepholeSubstituteAlternateSyntaxTest.java>
 #[cfg(test)]
 mod test {
     use oxc_allocator::Allocator;
 
-    use crate::{tester, CompressOptions};
+    use crate::tester;
 
     fn test(source_text: &str, expected: &str) {
         let allocator = Allocator::default();
-        let options = CompressOptions::default();
-        let mut pass = super::PeepholeSubstituteAlternateSyntax::new(options, false);
+        let mut pass = super::PeepholeSubstituteAlternateSyntax::new(false);
         tester::test(&allocator, source_text, expected, &mut pass);
     }
 
@@ -1197,20 +1176,4 @@ mod test {
         test("typeof foo !== `number`", "typeof foo != 'number'");
         test("`number` !== typeof foo", "'number' != typeof foo");
     }
-
-    #[test]
-    fn optional_catch_binding() {
-        test("try {} catch(e) {}", "try {} catch {}");
-        test_same("try {} catch([e]) {}");
-        test_same("try {} catch({e}) {}");
-
-        let allocator = Allocator::default();
-        let options = CompressOptions {
-            target: oxc_syntax::es_target::ESTarget::ES2018,
-            ..CompressOptions::default()
-        };
-        let mut pass = super::PeepholeSubstituteAlternateSyntax::new(options, false);
-        let code = "try {} catch(e) {}";
-        tester::test(&allocator, code, code, &mut pass);
-    }
 }

crates/oxc_minifier/src/ast_passes/remove_unused_code.rs

@@ -1,15 +1,18 @@
+use rustc_hash::FxHashSet;
+
 use oxc_allocator::Vec as ArenaVec;
 use oxc_ast::ast::*;
-use oxc_syntax::symbol::SymbolId;
+use oxc_syntax::{es_target::ESTarget, symbol::SymbolId};
 use oxc_traverse::{traverse_mut_with_ctx, ReusableTraverseCtx, Traverse, TraverseCtx};
-use rustc_hash::FxHashSet;
 
-use crate::CompressorPass;
+use crate::{CompressOptions, CompressorPass};
 
 /// Remove Unused Code
 ///
 /// <https://github.com/google/closure-compiler/blob/v20240609/src/com/google/javascript/jscomp/RemoveUnusedCode.java>
 pub struct RemoveUnusedCode {
+    options: CompressOptions,
+
     pub(crate) changed: bool,
 
     symbol_ids_to_remove: FxHashSet<SymbolId>,
@@ -58,30 +61,64 @@ impl<'a> Traverse<'a> for RemoveUnusedCode {
             }
         }
     }
+
+    fn exit_catch_clause(&mut self, catch: &mut CatchClause<'a>, _ctx: &mut TraverseCtx<'a>) {
+        self.compress_catch_clause(catch);
+    }
 }
 
 impl RemoveUnusedCode {
-    pub fn new() -> Self {
-        Self { changed: false, symbol_ids_to_remove: FxHashSet::default() }
+    pub fn new(options: CompressOptions) -> Self {
+        Self { options, changed: false, symbol_ids_to_remove: FxHashSet::default() }
+    }
+
+    fn compress_catch_clause(&mut self, catch: &mut CatchClause<'_>) {
+        if self.options.target >= ESTarget::ES2019 {
+            if let Some(param) = &catch.param {
+                if let BindingPatternKind::BindingIdentifier(ident) = &param.pattern.kind {
+                    if self.symbol_ids_to_remove.contains(&ident.symbol_id()) {
+                        catch.param = None;
+                        self.changed = true;
+                    }
+                }
+            };
+        }
     }
 }
 
 #[cfg(test)]
 mod test {
     use oxc_allocator::Allocator;
 
-    use crate::tester;
+    use crate::{tester, CompressOptions};
 
     fn test(source_text: &str, expected: &str) {
         let allocator = Allocator::default();
-        let mut pass = super::RemoveUnusedCode::new();
+        let options = CompressOptions::default();
+        let mut pass = super::RemoveUnusedCode::new(options);
         tester::test(&allocator, source_text, expected, &mut pass);
     }
 
     fn test_same(source_text: &str) {
         test(source_text, source_text);
     }
 
+    #[test]
+    fn optional_catch_binding() {
+        test("try {} catch(e) {}", "try {} catch {}");
+        test_same("try {} catch([e]) {}");
+        test_same("try {} catch({e}) {}");
+
+        let allocator = Allocator::default();
+        let options = CompressOptions {
+            target: oxc_syntax::es_target::ESTarget::ES2018,
+            ..CompressOptions::default()
+        };
+        let mut pass = super::RemoveUnusedCode::new(options);
+        let code = "try {} catch(e) {}";
+        tester::test(&allocator, code, code, &mut pass);
+    }
+
     #[test]
     fn simple() {
         test("var x", "");

crates/oxc_minifier/src/compressor.rs

@@ -34,7 +34,7 @@ impl<'a> Compressor<'a> {
     ) {
         let mut ctx = ReusableTraverseCtx::new(scopes, symbols, self.allocator);
         RemoveSyntax::new(self.options).build(program, &mut ctx);
-        RemoveUnusedCode::new().build(program, &mut ctx);
+        RemoveUnusedCode::new(self.options).build(program, &mut ctx);
         Normalize::new().build(program, &mut ctx);
         PeepholeOptimizations::new(true, self.options).run_in_loop(program, &mut ctx);
         PeepholeOptimizations::new(false, self.options).build(program, &mut ctx);

tasks/minsize/minsize.snap

@@ -5,23 +5,23 @@ Original   | minified   | minified   | gzip       | gzip       | Fixture
 
 173.90 kB  | 59.90 kB   | 59.82 kB   | 19.43 kB   | 19.33 kB   | moment.js 
 
-287.63 kB  | 90.39 kB   | 90.07 kB   | 32.12 kB   | 31.95 kB   | jquery.js 
+287.63 kB  | 90.37 kB   | 90.07 kB   | 32.10 kB   | 31.95 kB   | jquery.js 
 
-342.15 kB  | 118.48 kB  | 118.14 kB  | 44.54 kB   | 44.37 kB   | vue.js    
+342.15 kB  | 118.47 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 
 
 555.77 kB  | 273.58 kB  | 270.13 kB  | 90.98 kB   | 90.80 kB   | d3.js     
 
 1.01 MB    | 460.75 kB  | 458.89 kB  | 126.88 kB  | 126.71 kB  | bundle.min.js
 
-1.25 MB    | 653.17 kB  | 646.76 kB  | 163.57 kB  | 163.73 kB  | three.js  
+1.25 MB    | 653.16 kB  | 646.76 kB  | 163.57 kB  | 163.73 kB  | three.js  
 
-2.14 MB    | 726.70 kB  | 724.14 kB  | 180.25 kB  | 181.07 kB  | victory.js
+2.14 MB    | 726.69 kB  | 724.14 kB  | 180.25 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    | 493.00 kB  | 488.28 kB  | antd.js   
+6.69 MB    | 2.32 MB    | 2.31 MB    | 492.95 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.51 MB    | 3.49 MB    | 910.06 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.51 MB    | 3.49 MB    | 910.02 kB  | 915.50 kB  | typescript.js