feat(minifier): only constant fold numbers when result is smaller

crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs

@@ -30,6 +30,12 @@ impl<'a> Traverse<'a> for PeepholeFoldConstants {
     fn exit_expression(&mut self, expr: &mut Expression<'a>, ctx: &mut TraverseCtx<'a>) {
         let ctx = Ctx(ctx);
         if let Some(folded_expr) = match expr {
+            Expression::Identifier(ident) => (ident.name == "Infinity")
+                .then(|| {
+                    ctx.eval_to_number(expr)
+                        .map(|v| ctx.value_to_expr(expr.span(), ConstantValue::Number(v)))
+                })
+                .flatten(),
             Expression::CallExpression(e) => {
                 Self::try_fold_useless_object_dot_define_properties_call(e, ctx)
             }
@@ -246,9 +252,22 @@ impl<'a, 'b> PeepholeFoldConstants {
             | BinaryOperator::Division
             | BinaryOperator::Remainder
             | BinaryOperator::Multiplication
-            | BinaryOperator::Exponential => {
-                ctx.eval_binary_expression(e).map(|v| ctx.value_to_expr(e.span, v))
+            | BinaryOperator::Exponential => match (&e.left, &e.right) {
+                (Expression::NumericLiteral(left), Expression::NumericLiteral(right)) => {
+                    let value = ctx.eval_binary_expression(e)?;
+                    let ConstantValue::Number(num) = value else { return None };
+                    (num.is_nan()
+                        || num.is_infinite()
+                        || (num.abs() <= f64::powf(2.0, 53.0)
+                            && Self::approximate_printed_int_char_count(num)
+                                <= Self::approximate_printed_int_char_count(left.value)
+                                    + Self::approximate_printed_int_char_count(right.value)
+                                    + e.operator.as_str().len()))
+                    .then(|| value)
+                }
+                _ => ctx.eval_binary_expression(e),
             }
+            .map(|v| ctx.value_to_expr(e.span, v)),
             BinaryOperator::BitwiseAnd | BinaryOperator::BitwiseOR | BinaryOperator::BitwiseXOR => {
                 if let Some(v) = ctx.eval_binary_expression(e) {
                     return Some(ctx.value_to_expr(e.span, v));
@@ -260,6 +279,21 @@ impl<'a, 'b> PeepholeFoldConstants {
         }
     }
 
+    // https://github.com/evanw/esbuild/blob/v0.24.2/internal/js_ast/js_ast_helpers.go#L1128
+    fn approximate_printed_int_char_count(value: f64) -> usize {
+        let mut count = if value.is_infinite() {
+            "Infinity".len()
+        } else if value.is_nan() {
+            "NaN".len()
+        } else {
+            1 + 0.max(value.abs().log10().floor() as usize)
+        };
+        if value.is_sign_negative() {
+            count += 1;
+        }
+        count
+    }
+
     fn try_fold_left_child_op(
         e: &mut BinaryExpression<'a>,
         ctx: Ctx<'a, '_>,
@@ -1310,8 +1344,8 @@ mod test {
     #[test]
     fn test_fold_bitwise_op_additional() {
         test("x = null & 1", "x = 0");
-        test("x = (2 ** 31 - 1) | 1", "x = 2147483647");
-        test("x = (2 ** 31) | 1", "x = -2147483647");
+        test_same("x = (2 ** 31 - 1) | 1");
+        test_same("x = (2 ** 31) | 1");
 
         // https://github.com/oxc-project/oxc/issues/7944
         test_same("(x - 1) & 1");
@@ -1344,9 +1378,9 @@ mod test {
         test("x = 10 >>> 1", "x=5");
         test("x = 10 >>> 2", "x=2");
         test("x = 10 >>> 5", "x=0");
-        test("x = -1 >>> 1", "x=2147483647"); // 0x7fffffff
-        test("x = -1 >>> 0", "x=4294967295"); // 0xffffffff
-        test("x = -2 >>> 0", "x=4294967294"); // 0xfffffffe
+        test_same("x = -1 >>> 1");
+        test_same("x = -1 >>> 0");
+        test_same("x = -2 >>> 0");
         test("x = 0x90000000 >>> 28", "x=9");
 
         test("x = 0xffffffff << 0", "x=-1");

tasks/minsize/minsize.snap

@@ -9,17 +9,17 @@ Original   | minified   | minified   | gzip       | gzip       | Fixture
 
 342.15 kB  | 121.55 kB  | 118.14 kB  | 44.64 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  | 73.31 kB   | 72.48 kB   | 26.12 kB   | 26.20 kB   | lodash.js 
 
-555.77 kB  | 276.06 kB  | 270.13 kB  | 91.14 kB   | 90.80 kB   | d3.js     
+555.77 kB  | 275.92 kB  | 270.13 kB  | 91.13 kB   | 90.80 kB   | d3.js     
 
 1.01 MB    | 466.83 kB  | 458.89 kB  | 126.74 kB  | 126.71 kB  | bundle.min.js
 
-1.25 MB    | 661.47 kB  | 646.76 kB  | 163.94 kB  | 163.73 kB  | three.js  
+1.25 MB    | 661.43 kB  | 646.76 kB  | 163.92 kB  | 163.73 kB  | three.js  
 
-2.14 MB    | 740.44 kB  | 724.14 kB  | 181.35 kB  | 181.07 kB  | victory.js
+2.14 MB    | 740.33 kB  | 724.14 kB  | 181.33 kB  | 181.07 kB  | victory.js
 
-3.20 MB    | 1.02 MB    | 1.01 MB    | 332.00 kB  | 331.56 kB  | echarts.js
+3.20 MB    | 1.02 MB    | 1.01 MB    | 331.93 kB  | 331.56 kB  | echarts.js
 
 6.69 MB    | 2.39 MB    | 2.31 MB    | 495.62 kB  | 488.28 kB  | antd.js