improve compress granularity through typeofs (#2201)

fixes #2198
2017-07-05 19:20:33 +08:00
parent 5f046c724b
commit 1ac25fc032
4 changed files with 17 additions and 6 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -80,6 +80,7 @@ function Compressor(options, false_by_default) {
        switches      : !false_by_default,
        top_retain    : null,
        toplevel      : !!(options && options["top_retain"]),
+        typeofs       : !false_by_default,
        unsafe        : false,
        unsafe_comps  : false,
        unsafe_Func   : false,
@@ -3591,7 +3592,8 @@ merge(Compressor.prototype, {
          case "==":
          case "!=":
            // "undefined" == typeof x => undefined === x
-            if (self.left instanceof AST_String
+            if (compressor.option("typeofs")
+                && self.left instanceof AST_String
                && self.left.value == "undefined"
                && self.right instanceof AST_UnaryPrefix
                && self.right.operator == "typeof") {