introduce "strict" to `pure_getters` (#1795)

1 files changed, 9 insertions, 6 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 8df6e58f..c199d13f 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -71,7 +71,7 @@ function Compressor(options, false_by_default) {
         negate_iife   : !false_by_default,
         passes        : 1,
         properties    : !false_by_default,
-        pure_getters  : false,
+        pure_getters  : !false_by_default && "strict",
         pure_funcs    : null,
         reduce_vars   : !false_by_default,
         screw_ie8     : true,
@@ -1165,7 +1165,13 @@ merge(Compressor.prototype, {
     // may_eq_null()
     // returns true if this node may evaluate to null or undefined
     (function(def) {
-        def(AST_Node, return_true);
+        function is_strict(compressor) {
+            return /strict/.test(compressor.option("pure_getters"));
+        }
+
+        def(AST_Node, function(compressor) {
+            return !is_strict(compressor);
+        });
         def(AST_Null, return_true);
         def(AST_Undefined, return_true);
         def(AST_Constant, return_false);
@@ -1198,12 +1204,9 @@ merge(Compressor.prototype, {
         def(AST_Seq, function(compressor) {
             return this.cdr.may_eq_null(compressor);
         });
-        def(AST_PropAccess, function(compressor) {
-            return !compressor.option("unsafe");
-        });
         def(AST_SymbolRef, function(compressor) {
             if (this.is_undefined) return true;
-            if (compressor.option("unsafe")) return false;
+            if (!is_strict(compressor)) return false;
             var fixed = this.fixed_value();
             return !fixed || fixed.may_eq_null(compressor);
         });