feat(minifier): add Normalize ast pass

crates/oxc_minifier/src/ast_passes/mod.rs

@@ -4,6 +4,7 @@ use oxc_traverse::{traverse_mut_with_ctx, ReusableTraverseCtx, Traverse, Travers
 
 mod collapse_variable_declarations;
 mod exploit_assigns;
+mod normalize;
 mod peephole_fold_constants;
 mod peephole_minimize_conditions;
 mod peephole_remove_dead_code;
@@ -14,6 +15,7 @@ mod statement_fusion;
 
 pub use collapse_variable_declarations::CollapseVariableDeclarations;
 pub use exploit_assigns::ExploitAssigns;
+pub use normalize::Normalize;
 pub use peephole_fold_constants::PeepholeFoldConstants;
 pub use peephole_minimize_conditions::PeepholeMinimizeConditions;
 pub use peephole_remove_dead_code::PeepholeRemoveDeadCode;

crates/oxc_minifier/src/ast_passes/normalize.rs

@@ -0,0 +1,67 @@
+use oxc_ast::ast::*;
+use oxc_syntax::scope::ScopeFlags;
+use oxc_traverse::{traverse_mut_with_ctx, ReusableTraverseCtx, Traverse, TraverseCtx};
+
+use crate::CompressorPass;
+
+/// Normalize AST
+///
+/// Make subsequent AST passes easier to analyze:
+///
+/// * convert whiles to fors
+///
+/// <https://github.com/google/closure-compiler/blob/v20240609/src/com/google/javascript/jscomp/Normalize.java>
+pub struct Normalize;
+
+impl<'a> CompressorPass<'a> for Normalize {
+    fn build(&mut self, program: &mut Program<'a>, ctx: &mut ReusableTraverseCtx<'a>) {
+        traverse_mut_with_ctx(self, program, ctx);
+    }
+}
+
+impl<'a> Traverse<'a> for Normalize {
+    fn exit_statement(&mut self, stmt: &mut Statement<'a>, ctx: &mut TraverseCtx<'a>) {
+        if matches!(stmt, Statement::WhileStatement(_)) {
+            Self::convert_while_to_for(stmt, ctx);
+        }
+    }
+}
+
+impl<'a> Normalize {
+    pub fn new() -> Self {
+        Self
+    }
+
+    fn convert_while_to_for(stmt: &mut Statement<'a>, ctx: &mut TraverseCtx<'a>) {
+        let Statement::WhileStatement(while_stmt) = ctx.ast.move_statement(stmt) else { return };
+        let while_stmt = while_stmt.unbox();
+        let for_stmt = ctx.ast.alloc_for_statement_with_scope_id(
+            while_stmt.span,
+            None,
+            Some(while_stmt.test),
+            None,
+            while_stmt.body,
+            ctx.create_child_scope_of_current(ScopeFlags::empty()),
+        );
+        *stmt = Statement::ForStatement(for_stmt);
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use oxc_allocator::Allocator;
+
+    use crate::tester;
+
+    fn test(source_text: &str, expected: &str) {
+        let allocator = Allocator::default();
+        let mut pass = super::Normalize::new();
+        tester::test(&allocator, source_text, expected, &mut pass);
+    }
+
+    #[test]
+    fn test_while() {
+        // Verify while loops are converted to FOR loops.
+        test("while(c < b) foo()", "for(; c < b;) foo()");
+    }
+}

crates/oxc_minifier/src/compressor.rs

@@ -5,8 +5,8 @@ use oxc_traverse::ReusableTraverseCtx;
 
 use crate::{
     ast_passes::{
-        CollapsePass, DeadCodeElimination, LatePeepholeOptimizations, PeepholeOptimizations,
-        RemoveSyntax,
+        CollapsePass, DeadCodeElimination, LatePeepholeOptimizations, Normalize,
+        PeepholeOptimizations, RemoveSyntax,
     },
     CompressOptions, CompressorPass,
 };
@@ -35,6 +35,7 @@ impl<'a> Compressor<'a> {
     ) {
         let mut ctx = ReusableTraverseCtx::new(scopes, symbols, self.allocator);
         RemoveSyntax::new(self.options).build(program, &mut ctx);
+        Normalize::new().build(program, &mut ctx);
         PeepholeOptimizations::new().build(program, &mut ctx);
         CollapsePass::new().build(program, &mut ctx);
         LatePeepholeOptimizations::new().run_in_loop(program, &mut ctx);

tasks/minsize/minsize.snap

@@ -5,23 +5,23 @@ Original   | minified   | minified   | gzip       | gzip       | Fixture
 
 173.90 kB  | 61.52 kB   | 59.82 kB   | 19.54 kB   | 19.33 kB   | moment.js 
 
-287.63 kB  | 92.47 kB   | 90.07 kB   | 32.30 kB   | 31.95 kB   | jquery.js 
+287.63 kB  | 92.42 kB   | 90.07 kB   | 32.32 kB   | 31.95 kB   | jquery.js 
 
-342.15 kB  | 121.36 kB  | 118.14 kB  | 44.67 kB   | 44.37 kB   | vue.js    
+342.15 kB  | 121.31 kB  | 118.14 kB  | 44.69 kB   | 44.37 kB   | vue.js    
 
-544.10 kB  | 73.32 kB   | 72.48 kB   | 26.13 kB   | 26.20 kB   | lodash.js 
+544.10 kB  | 73.22 kB   | 72.48 kB   | 26.22 kB   | 26.20 kB   | lodash.js 
 
-555.77 kB  | 275.77 kB  | 270.13 kB  | 91.12 kB   | 90.80 kB   | d3.js     
+555.77 kB  | 275.67 kB  | 270.13 kB  | 91.19 kB   | 90.80 kB   | d3.js     
 
-1.01 MB    | 466.38 kB  | 458.89 kB  | 126.72 kB  | 126.71 kB  | bundle.min.js
+1.01 MB    | 466.33 kB  | 458.89 kB  | 126.76 kB  | 126.71 kB  | bundle.min.js
 
-1.25 MB    | 660.41 kB  | 646.76 kB  | 163.99 kB  | 163.73 kB  | three.js  
+1.25 MB    | 660.39 kB  | 646.76 kB  | 164.00 kB  | 163.73 kB  | three.js  
 
-2.14 MB    | 740.08 kB  | 724.14 kB  | 181.34 kB  | 181.07 kB  | victory.js
+2.14 MB    | 739.97 kB  | 724.14 kB  | 181.42 kB  | 181.07 kB  | victory.js
 
-3.20 MB    | 1.02 MB    | 1.01 MB    | 332.26 kB  | 331.56 kB  | echarts.js
+3.20 MB    | 1.02 MB    | 1.01 MB    | 332.30 kB  | 331.56 kB  | echarts.js
 
-6.69 MB    | 2.39 MB    | 2.31 MB    | 495.65 kB  | 488.28 kB  | antd.js   
+6.69 MB    | 2.39 MB    | 2.31 MB    | 495.67 kB  | 488.28 kB  | antd.js   
 
-10.95 MB   | 3.54 MB    | 3.49 MB    | 909.94 kB  | 915.50 kB  | typescript.js
+10.95 MB   | 3.54 MB    | 3.49 MB    | 910.07 kB  | 915.50 kB  | typescript.js