improve `RegExp` handling (#1959)

- remove `options.output.unescape_regexps`
- preserve original pattern whenever possible

fixes #54
fixes #1929

1 files changed, 9 insertions, 0 deletions

diff --git a/test/compress/string-literal.js b/test/compress/string-literal.js
index 8b93961c..1138fed8 100644
--- a/test/compress/string-literal.js
+++ b/test/compress/string-literal.js
@@ -8,3 +8,12 @@ octal_escape_sequence: {
         var border_check = "\x20\x30\x38\x30\x00\x30\xc0\x30";
     }
 }
+
+issue_1929: {
+    input: {
+        function f(s) {
+            return s.split(/[\\/]/);
+        }
+    }
+    expect_exact: "function f(s){return s.split(/[\\\\/]/)}"
+}