handle circular structures

Author: nkaradzhov

packages/client/lib/single-entry-cache.spec.ts

@@ -70,4 +70,16 @@ describe('SingleEntryCache', () => {
 
     assert.strictEqual(cache.get(keyObj2), undefined);
   });
+
+  it('should handle circular structures', () => {
+    const keyObj: any = {};
+    keyObj.self = keyObj;
+
+    const instance = { data: 'test data' };
+    
+    cache.set(keyObj, instance);
+    
+    assert.strictEqual(cache.get(keyObj), instance);
+  });
+
 });

packages/client/lib/single-entry-cache.ts

@@ -1,25 +1,36 @@
+function makeCircularReplacer() {
+  const seen = new WeakSet();
+  return function serialize(_: string, value: any) {
+    if (value && typeof value === 'object') {
+      if (seen.has(value)) {
+        return 'circular';
+      }
+      seen.add(value);
+      return value;
+    }
+    return value;
+  }
+}
 export default class SingleEntryCache {
   #cached?: any;
   #key?: string;
 
   /**
    * Retrieves an instance from the cache based on the provided key object.
-   * 
+   *
    * @param keyObj - The key object to look up in the cache.
    * @returns The cached instance if found, undefined otherwise.
-   * 
+   *
    * @remarks
    * This method uses JSON.stringify for comparison, which may not work correctly
    * if the properties in the key object are rearranged or reordered.
    */
   get(keyObj?: object) {
-    return JSON.stringify(keyObj) === this.#key
-      ? this.#cached
-      : undefined;
+    return JSON.stringify(keyObj, makeCircularReplacer()) === this.#key ? this.#cached : undefined;
   }
 
   set(keyObj: object | undefined, obj: any) {
     this.#cached = obj;
-    this.#key = JSON.stringify(keyObj);
+    this.#key = JSON.stringify(keyObj, makeCircularReplacer());
   }
 }