feat(minifier): fold (!0).toString() to true (#12938)

crates/oxc_ecmascript/src/constant_evaluation/call_expr.rs

@@ -324,16 +324,14 @@ fn try_fold_to_string<'a>(
             let result = format_radix(i, radix);
             Some(ConstantValue::String(Cow::Owned(result)))
         }
-        // `null` returns type errors
-        Expression::BooleanLiteral(_)
-        | Expression::NumericLiteral(_)
-        | Expression::BigIntLiteral(_)
-        | Expression::RegExpLiteral(_)
-        | Expression::StringLiteral(_)
-            if args.is_empty() =>
-        {
-            object.to_js_string(ctx).map(ConstantValue::String)
+        Expression::RegExpLiteral(lit) if args.is_empty() => {
+            lit.to_js_string(ctx).map(ConstantValue::String)
         }
+        e if args.is_empty() => e
+            .evaluate_value(ctx)
+            // `null` and `undefined` returns type errors
+            .filter(|v| !v.is_undefined() && !v.is_null())
+            .and_then(|v| v.to_js_string(ctx).map(ConstantValue::String)),
         _ => None,
     }
 }

crates/oxc_ecmascript/src/constant_evaluation/value.rs

@@ -36,6 +36,10 @@ impl<'a> ConstantValue<'a> {
         matches!(self, Self::Undefined)
     }
 
+    pub fn is_null(&self) -> bool {
+        matches!(self, Self::Null)
+    }
+
     pub fn into_string(self) -> Option<Cow<'a, str>> {
         match self {
             Self::String(s) => Some(s),

crates/oxc_minifier/src/peephole/replace_known_methods.rs

@@ -1486,6 +1486,8 @@ mod test {
         test("x = false['toString']()", "x = 'false';");
         test("x = false.toString()", "x = 'false';");
         test("x = true.toString()", "x = 'true';");
+        test("x = (!0).toString()", "x = 'true';");
+        test("x = (!1).toString()", "x = 'false';");
         test("x = 'xy'.toString()", "x = 'xy';");
         test("x = 0 .toString()", "x = '0';");
         test("x = 123 .toString()", "x = '123';");