1 files changed, 3 insertions, 1 deletions
diff --git a/lib/output.js b/lib/output.js
index 592717b0..49164359 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -753,7 +753,9 @@ function OutputStream(options) {
         if (p instanceof AST_Binary) {
             var po = p.operator, pp = PRECEDENCE[po];
             var so = this.operator, sp = PRECEDENCE[so];
-            return pp > sp || (pp == sp && this === p[po == "**" ? "left" : "right"]);
+            return pp > sp
+                || po == "??" && (so == "&&" || so == "||")
+                || (pp == sp && this === p[po == "**" ? "left" : "right"]);
         }
         // (foo && bar)()
         if (p instanceof AST_Call) return p.expression === this;