fix #1066

src/core/util.ts

@@ -75,19 +75,23 @@ export function logError(...args: any[]) {
  * (There might be a large number of date in `series.data`).
  * So date should not be modified in and out of echarts.
  */
-export function clone<T extends any>(source: T): T {
+function cloneHelper<T extends any>(source: T, alreadyCloned: Map<Object, Object>): T {
     if (source == null || typeof source !== 'object') {
         return source;
     }
+    if (alreadyCloned.has(source)) {
+        return alreadyCloned.get(source) as T;
+    }
 
     let result = source as any;
     const typeStr = <string>objToString.call(source);
 
     if (typeStr === '[object Array]') {
         if (!isPrimitive(source)) {
             result = [] as any;
+            alreadyCloned.set(source, []);
             for (let i = 0, len = (source as any[]).length; i < len; i++) {
-                result[i] = clone((source as any[])[i]);
+                result[i] = cloneHelper((source as any[])[i], alreadyCloned);
             }
         }
     }
@@ -108,17 +112,24 @@ export function clone<T extends any>(source: T): T {
     }
     else if (!BUILTIN_OBJECT[typeStr] && !isPrimitive(source) && !isDom(source)) {
         result = {} as any;
+        alreadyCloned.set(source, result);
         for (let key in source) {
             // Check if key is __proto__ to avoid prototype pollution
             if (source.hasOwnProperty(key) && key !== protoKey) {
-                result[key] = clone(source[key]);
+                result[key] = cloneHelper(source[key], alreadyCloned);
             }
         }
     }
 
+    alreadyCloned.delete(source);
     return result;
 }
 
+export function clone<T extends any>(source: T): T {
+    const alreadyCloned = new Map<Object, Object>();
+    return cloneHelper(source, alreadyCloned);
+}
+
 export function merge<
     T extends Dictionary<any>,
     S extends Dictionary<any>

test/ut/spec/core/util.test.ts

@@ -146,5 +146,33 @@ describe('zrUtil', function() {
 
         });
 
+        it("circular", function () {
+            class TreeNode {
+                public children: TreeNode[]
+                public parent: TreeNode | null
+
+                constructor(parent: TreeNode = null, children: TreeNode[] = []) {
+                    this.children = children;
+                    this.parent = parent;
+                }
+            }
+
+            const root = new TreeNode();
+            const a = new TreeNode(root, [new TreeNode(), new TreeNode()]);
+            a.children.forEach(c => c.parent = a);
+            root.children.push(a)
+            root.children.push(new TreeNode(root, [new TreeNode()]))
+            expect(zrUtil.clone(root)).toEqual(root);
+
+            const b: { key: any } = {key: null};
+            b.key = b;
+            const bCloned = zrUtil.clone(b);
+            expect(bCloned === b).toBeFalsy();
+            expect(bCloned.key === b).toBeFalsy();
+            expect(bCloned === b.key).toBeFalsy();
+            expect(bCloned.key === b.key).toBeFalsy();
+            expect(bCloned).toEqual(b);
+        });
+
     });
 });