improve `evaluate` on `typeof` (#2550)

- gated through `typeofs`

1 files changed, 7 insertions, 3 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 5301d48f..7d87c4a6 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1828,12 +1828,17 @@ merge(Compressor.prototype, {
             return this;
         });
         def(AST_UnaryPrefix, function(compressor){
+            var e = this.expression;
             // Function would be evaluated to an array and so typeof would
             // incorrectly return 'object'. Hence making is a special case.
-            if (this.operator == "typeof" && this.expression instanceof AST_Function) {
+            if (compressor.option("typeofs")
+                && this.operator == "typeof"
+                && (e instanceof AST_Lambda
+                    || e instanceof AST_SymbolRef
+                        && e.fixed_value() instanceof AST_Lambda)) {
                 return typeof function(){};
             }
-            var e = ev(this.expression, compressor);
+            e = ev(e, compressor);
             if (e === this.expression) return this;
             switch (this.operator) {
               case "!": return !e;
@@ -1894,7 +1899,6 @@ merge(Compressor.prototype, {
             return value === node ? this : value;
         });
         def(AST_SymbolRef, function(compressor){
-            if (!compressor.option("reduce_vars")) return this;
             var fixed = this.fixed_value();
             if (!fixed) return this;
             this._eval = return_this;