[Fix] stringify: cyclic reference

ljharb · Dec 4, 2021 · ec25fbd · ec25fbd
1 parent 24c19cc
commit ec25fbd
Showing 1 changed file with 21 additions and 3 deletions.
diff --git a/lib/stringify.js b/lib/stringify.js
@@ -56,6 +56,8 @@ var isNonNullishPrimitive = function isNonNullishPrimitive(v) {
         || typeof v === 'bigint';
 };
 
+var scSym = Symbol('SideChannel');
+
 var stringify = function stringify(
     object,
     prefix,
@@ -75,8 +77,23 @@ var stringify = function stringify(
 ) {
     var obj = object;
 
-    if (sideChannel.has(object)) {
-        throw new RangeError('Cyclic object value');
+    var tmpSc = sideChannel;
+    var step = 0;
+    var findFlag = false;
+    while ((tmpSc = tmpSc.get(scSym)) !== undefined && !findFlag) {
+        // Where object last appeared in the ref tree
+        var pos = tmpSc.get(object);
+        step += 1;
+        if (pos != undefined) {
+            if (pos === step) {
+                throw new RangeError('Cyclic object value');
+            } else {
+                findFlag = true; // Break while
+            }
+        }
+        if (tmpSc.get(scSym) === undefined) {
+            step = 0;
+        }
     }
 
     if (typeof filter === 'function') {
@@ -145,8 +162,9 @@ var stringify = function stringify(
             ? typeof generateArrayPrefix === 'function' ? generateArrayPrefix(prefix, key) : prefix
             : prefix + (allowDots ? '.' + key : '[' + key + ']');
 
-        sideChannel.set(object, true);
+        sideChannel.set(object, step);
         var valueSideChannel = getSideChannel();
+        valueSideChannel.set(scSym, sideChannel);
         pushToArray(values, stringify(
             value,
             keyPrefix,