feat(minifier: implement folding of simple function calls

oxc-project · Oct 12, 2024 · 5439201 · 5439201
1 parent bbca743
commit 5439201
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Showing 2 changed files with 42 additions and 6 deletions.
diff --git a/crates/oxc_minifier/src/ast_passes/peephole_substitute_alternate_syntax.rs b/crates/oxc_minifier/src/ast_passes/peephole_substitute_alternate_syntax.rs
@@ -96,7 +96,13 @@ impl<'a> Traverse<'a> for PeepholeSubstituteAlternateSyntax {
                 }
             }
             Expression::CallExpression(call_expr) => {
-                if let Some(call_expr) = Self::try_fold_call_expression(call_expr, ctx) {
+                if let Some(call_expr) =
+                    Self::try_fold_literal_constructor_call_expression(call_expr, ctx)
+                {
+                    *expr = call_expr;
+                    self.changed = true;
+                } else if let Some(call_expr) = Self::try_fold_simple_function_call(call_expr, ctx)
+                {
                     *expr = call_expr;
                     self.changed = true;
                 }
@@ -398,7 +404,7 @@ impl<'a> PeepholeSubstituteAlternateSyntax {
         }
     }
 
-    fn try_fold_call_expression(
+    fn try_fold_literal_constructor_call_expression(
         call_expr: &mut CallExpression<'a>,
         ctx: &mut TraverseCtx<'a>,
     ) -> Option<Expression<'a>> {
@@ -452,6 +458,37 @@ impl<'a> PeepholeSubstituteAlternateSyntax {
         }
     }
 
+    fn try_fold_simple_function_call(
+        call_expr: &mut CallExpression<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) -> Option<Expression<'a>> {
+        if call_expr.optional || call_expr.arguments.len() != 1 {
+            return None;
+        }
+        if call_expr.callee.is_global_reference_name("Boolean", ctx.symbols()) {
+            // TODO
+            None
+        } else if call_expr.callee.is_global_reference_name("String", ctx.symbols()) {
+            // `String(a)` -> `'' + (a)`
+            let arg = call_expr.arguments.get_mut(0).and_then(|arg| arg.as_expression_mut())?;
+
+            if !matches!(arg, Expression::Identifier(_) | Expression::CallExpression(_))
+                && !arg.is_literal()
+            {
+                return None;
+            }
+
+            Some(ctx.ast.expression_binary(
+                call_expr.span,
+                ctx.ast.expression_from_string_literal(ctx.ast.string_literal(SPAN, "")),
+                BinaryOperator::Addition,
+                ctx.ast.move_expression(arg),
+            ))
+        } else {
+            None
+        }
+    }
+
     fn try_fold_chain_call_expression(
         &mut self,
         call_expr: &mut CallExpression<'a>,
@@ -830,7 +867,6 @@ mod test {
     }
 
     #[test]
-    #[ignore]
     fn test_simple_function_call1() {
         test("var a = String(23)", "var a = '' + 23");
         // Don't fold the existence check to preserve behavior

diff --git a/tasks/minsize/minsize.snap b/tasks/minsize/minsize.snap
@@ -6,15 +6,15 @@ Original   | Minified   | esbuild    | Gzip       | esbuild
 
 287.63 kB  | 92.83 kB   | 90.07 kB   | 32.29 kB   | 31.95 kB   | jquery.js 
 
-342.15 kB  | 124.11 kB  | 118.14 kB  | 44.80 kB   | 44.37 kB   | vue.js    
+342.15 kB  | 124.06 kB  | 118.14 kB  | 44.79 kB   | 44.37 kB   | vue.js    
 
 544.10 kB  | 74.13 kB   | 72.48 kB   | 26.23 kB   | 26.20 kB   | lodash.js 
 
 555.77 kB  | 278.22 kB  | 270.13 kB  | 91.36 kB   | 90.80 kB   | d3.js     
 
-1.01 MB    | 470.11 kB  | 458.89 kB  | 126.97 kB  | 126.71 kB  | bundle.min.js
+1.01 MB    | 470.08 kB  | 458.89 kB  | 126.96 kB  | 126.71 kB  | bundle.min.js
 
-1.25 MB    | 670.96 kB  | 646.76 kB  | 164.72 kB  | 163.73 kB  | three.js  
+1.25 MB    | 670.94 kB  | 646.76 kB  | 164.72 kB  | 163.73 kB  | three.js  
 
 2.14 MB    | 756.32 kB  | 724.14 kB  | 182.74 kB  | 181.07 kB  | victory.js