optimize conditional when condition symbol matches consequent (#1684)

2017-03-26 04:36:33 -04:00
parent 94f84727ce
commit 5509e51098
2 changed files with 40 additions and 0 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3565,8 +3565,19 @@ merge(Compressor.prototype, {
                alternative: self.consequent
            });
        }
+        var condition = self.condition;
        var consequent = self.consequent;
        var alternative = self.alternative;
+        // x?x:y --> x||y
+        if (condition instanceof AST_SymbolRef
+            && consequent instanceof AST_SymbolRef
+            && condition.definition() === consequent.definition()) {
+            return make_node(AST_Binary, self, {
+                operator: "||",
+                left: condition,
+                right: alternative
+            });
+        }
        // if (foo) exp = something; else exp = something_else;
        //                   |
        //                   v