feat(minifier): reenable minifier tests (#969)

crates/oxc_minifier/src/compressor/mod.rs

@@ -2,6 +2,7 @@
 
 mod ast_util;
 mod fold;
+mod prepass;
 mod util;
 
 use oxc_allocator::{Allocator, Vec};
@@ -14,6 +15,8 @@ use oxc_syntax::{
     NumberBase,
 };
 
+use self::prepass::Prepass;
+
 #[allow(clippy::struct_excessive_bools)]
 #[derive(Debug, Clone, Copy)]
 pub struct CompressOptions {
@@ -70,16 +73,19 @@ impl Default for CompressOptions {
 pub struct Compressor<'a> {
     ast: AstBuilder<'a>,
     options: CompressOptions,
+
+    prepass: Prepass<'a>,
 }
 
 const SPAN: Span = Span::new(0, 0);
 
 impl<'a> Compressor<'a> {
     pub fn new(allocator: &'a Allocator, options: CompressOptions) -> Self {
-        Self { ast: AstBuilder::new(allocator), options }
+        Self { ast: AstBuilder::new(allocator), options, prepass: Prepass::new(allocator) }
     }
 
     pub fn build<'b>(mut self, program: &'b mut Program<'a>) {
+        self.prepass.visit_program(program);
         self.visit_program(program);
     }
 
@@ -208,16 +214,15 @@ impl<'a> Compressor<'a> {
     /* Expressions */
 
     /// Transforms `undefined` => `void 0`
-    fn compress_undefined<'b>(&mut self, _expr: &'b mut Expression<'a>) -> bool {
-        // let Expression::Identifier(ident) = expr else { return false };
-        // if let Some(reference_id) = ident.reference_id.clone().into_inner() {
-        // if ident.name == "undefined"
-        // && self.semantic.symbols().is_global_reference(reference_id)
-        // {
-        // *expr = self.create_void_0();
-        // return true;
-        // }
-        // }
+    fn compress_undefined<'b>(&mut self, expr: &'b mut Expression<'a>) -> bool {
+        let Expression::Identifier(ident) = expr else { return false };
+        if ident.name == "undefined" {
+            // if let Some(reference_id) = ident.reference_id.clone().into_inner() {
+            // && self.semantic.symbols().is_global_reference(reference_id)
+            *expr = self.create_void_0();
+            return true;
+            // }
+        }
         false
     }
 
@@ -225,13 +230,13 @@ impl<'a> Compressor<'a> {
     #[allow(unused)]
     fn compress_infinity<'b>(&mut self, expr: &'b mut Expression<'a>) -> bool {
         let Expression::Identifier(ident) = expr else { return false };
-        // if let Some(reference_id) = ident.reference_id.clone().into_inner() {
-        // if ident.name == "Infinity" && self.semantic.symbols().is_global_reference(reference_id)
-        // {
-        // *expr = self.create_one_div_zero();
-        // return true;
-        // }
-        // }
+        if ident.name == "Infinity" {
+            // if let Some(reference_id) = ident.reference_id.clone().into_inner() {
+            //&& self.semantic.symbols().is_global_reference(reference_id)
+            *expr = self.create_one_div_zero();
+            return true;
+            // }
+        }
         false
     }
 
@@ -319,7 +324,18 @@ impl<'a> Compressor<'a> {
 
 impl<'a, 'b> VisitMut<'a, 'b> for Compressor<'a> {
     fn visit_statements(&mut self, stmts: &'b mut Vec<'a, Statement<'a>>) {
-        stmts.retain(|stmt| !(self.drop_debugger(stmt) || self.drop_console(stmt)));
+        stmts.retain(|stmt| {
+            if matches!(stmt, Statement::EmptyStatement(_)) {
+                return false;
+            }
+            if self.drop_debugger(stmt) {
+                return false;
+            }
+            if self.drop_console(stmt) {
+                return false;
+            }
+            true
+        });
 
         self.join_vars(stmts);
 

crates/oxc_minifier/src/compressor/prepass.rs

@@ -0,0 +1,28 @@
+use oxc_allocator::Allocator;
+
+#[allow(clippy::wildcard_imports)]
+use oxc_ast::{ast::*, AstBuilder, VisitMut};
+
+pub struct Prepass<'a> {
+    ast: AstBuilder<'a>,
+}
+
+impl<'a> Prepass<'a> {
+    pub fn new(allocator: &'a Allocator) -> Self {
+        Self { ast: AstBuilder::new(allocator) }
+    }
+
+    fn strip_parenthesized_expression<'b>(&self, expr: &'b mut Expression<'a>) {
+        if let Expression::ParenthesizedExpression(paren_expr) = expr {
+            *expr = self.ast.move_expression(&mut paren_expr.expression);
+            self.strip_parenthesized_expression(expr);
+        }
+    }
+}
+
+impl<'a, 'b> VisitMut<'a, 'b> for Prepass<'a> {
+    fn visit_expression(&mut self, expr: &'b mut Expression<'a>) {
+        self.strip_parenthesized_expression(expr);
+        self.visit_expression_match(expr);
+    }
+}

crates/oxc_minifier/src/printer/gen.rs

@@ -76,8 +76,9 @@ impl<'a> Gen for Statement<'a> {
             Self::BreakStatement(stmt) => stmt.gen(p, ctx),
             Self::ContinueStatement(stmt) => stmt.gen(p, ctx),
             Self::DebuggerStatement(stmt) => stmt.gen(p, ctx),
+            Self::Declaration(decl) => decl.gen(p, ctx),
             Self::DoWhileStatement(stmt) => stmt.gen(p, ctx),
-            Self::EmptyStatement(decl) => {}
+            Self::EmptyStatement(stmt) => stmt.gen(p, ctx),
             Self::ExpressionStatement(stmt) => stmt.gen(p, ctx),
             Self::ForInStatement(stmt) => stmt.gen(p, ctx),
             Self::ForOfStatement(stmt) => stmt.gen(p, ctx),
@@ -91,7 +92,6 @@ impl<'a> Gen for Statement<'a> {
             Self::TryStatement(stmt) => stmt.gen(p, ctx),
             Self::WhileStatement(stmt) => stmt.gen(p, ctx),
             Self::WithStatement(stmt) => stmt.gen(p, ctx),
-            Self::Declaration(decl) => decl.gen(p, ctx),
         }
     }
 }
@@ -295,6 +295,12 @@ impl<'a> Gen for DoWhileStatement<'a> {
     }
 }
 
+impl Gen for EmptyStatement {
+    fn gen(&self, p: &mut Printer, ctx: Context) {
+        p.print(b';');
+    }
+}
+
 impl Gen for ContinueStatement {
     fn gen(&self, p: &mut Printer, ctx: Context) {
         p.print_str(b"continue");
@@ -768,6 +774,9 @@ impl<'a> GenExpr for Expression<'a> {
             Self::ClassExpression(expr) => expr.gen(p, ctx),
             Self::JSXElement(el) => el.gen(p, ctx),
             Self::JSXFragment(fragment) => fragment.gen(p, ctx),
+            Self::ParenthesizedExpression(_) => {
+                panic!("The compressor mut strip this ParenthesizedExpression.")
+            }
             _ => {}
         }
     }

crates/oxc_minifier/tests/mod.rs

@@ -14,10 +14,10 @@ pub(crate) fn test(source_text: &str, expected: &str) {
     test_with_options(source_text, expected, options);
 }
 
-pub(crate) fn test_with_options(source_text: &str, _expected: &str, options: MinifierOptions) {
+pub(crate) fn test_with_options(source_text: &str, expected: &str, options: MinifierOptions) {
     let source_type = SourceType::default();
-    let _minified = Minifier::new(source_text, source_type, options).build();
-    // assert_eq!(expected, minified, "for source {source_text}");
+    let minified = Minifier::new(source_text, source_type, options).build();
+    assert_eq!(expected, minified, "for source {source_text}");
 }
 
 pub(crate) fn test_same(source_text: &str) {
@@ -28,17 +28,17 @@ pub(crate) fn test_reparse(source_text: &str) {
     let source_type = SourceType::default();
     let options = MinifierOptions { mangle: false, ..MinifierOptions::default() };
     let minified = Minifier::new(source_text, source_type, options).build();
-    let _minified2 = Minifier::new(&minified, source_type, options).build();
-    // assert_eq!(minified, minified2, "for source {source_text}");
+    let minified2 = Minifier::new(&minified, source_type, options).build();
+    assert_eq!(minified, minified2, "for source {source_text}");
 }
 
-pub(crate) fn test_without_compress_booleans(source_text: &str, _expected: &str) {
+pub(crate) fn test_without_compress_booleans(source_text: &str, expected: &str) {
     let source_type = SourceType::default();
     let compress_options = CompressOptions { booleans: false, ..CompressOptions::default() };
     let options =
         MinifierOptions { mangle: false, compress: compress_options, print: PrinterOptions };
-    let _minified = Minifier::new(source_text, source_type, options).build();
-    // assert_eq!(expected, minified, "for source {source_text}");
+    let minified = Minifier::new(source_text, source_type, options).build();
+    assert_eq!(expected, minified, "for source {source_text}");
 }
 
 pub(crate) fn test_snapshot<S>(name: &str, sources: S)