fix: Decycling of objects (#1839)

* fix: Decycling of objects

* fix: Add changelog

* fix: CodeReview

* fix: Use isPrimitive

Author: HazAT

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ## 4.5.2
 
+- [utils] fix: Decycling for objects to no produce an endless loop
 - [browser] fix: <unlabeled> event for unhandledRejection
 - [loader] fix: Handle unhandledRejection the same way as it would be thrown
 

packages/utils/src/memo.ts

@@ -0,0 +1,55 @@
+// tslint:disable:no-unsafe-any
+/**
+ * Memo class used for decycle json objects. Uses WeakSet if available otherwise array.
+ */
+export class Memo {
+  /** Determines if WeakSet is available */
+  private readonly hasWeakSet: boolean;
+  /** Either WeakSet or Array */
+  private readonly inner: any;
+
+  public constructor() {
+    // tslint:disable-next-line
+    this.hasWeakSet = typeof WeakSet === 'function';
+    this.inner = this.hasWeakSet ? new WeakSet() : [];
+  }
+
+  /**
+   * Sets obj to remember.
+   * @param obj Object to remember
+   */
+  public memoize(obj: any): boolean {
+    if (this.hasWeakSet) {
+      if (this.inner.has(obj)) {
+        return true;
+      }
+      this.inner.add(obj);
+      return false;
+    } else {
+      for (const value of this.inner) {
+        if (value === obj) {
+          return true;
+        }
+      }
+      this.inner.push(obj);
+      return false;
+    }
+  }
+
+  /**
+   * Removes object from internal storage.
+   * @param obj Object to forget
+   */
+  public unmemoize(obj: any): void {
+    if (this.hasWeakSet) {
+      this.inner.delete(obj);
+    } else {
+      for (let i = 0; i < this.inner.length; i++) {
+        if (this.inner[i] === obj) {
+          this.inner.splice(i, 1);
+          break;
+        }
+      }
+    }
+  }
+}

packages/utils/src/object.ts

@@ -1,5 +1,6 @@
 import { SentryWrappedFunction } from '@sentry/types';
-import { isNaN, isPlainObject, isUndefined } from './is';
+import { isNaN, isPlainObject, isPrimitive, isUndefined } from './is';
+import { Memo } from './memo';
 import { truncate } from './string';
 
 /**
@@ -294,6 +295,27 @@ function normalizeValue(value: any, key?: any): any {
   return value;
 }
 
+/**
+ * Decycles an object to make it safe for json serialization.
+ *
+ * @param obj Object to be decycled
+ * @param memo Optional Memo class handling decycling
+ */
+function decycle(obj: any, memo: Memo = new Memo()): any {
+  if (!isPrimitive(obj)) {
+    if (memo.memoize(obj)) {
+      return '[Circular ~]';
+    }
+    // tslint:disable-next-line
+    for (const key in obj) {
+      // tslint:disable-next-line
+      obj[key] = decycle(obj[key], memo);
+    }
+    memo.unmemoize(obj);
+  }
+  return obj;
+}
+
 /**
  * serializer()
  *
@@ -302,39 +324,8 @@ function normalizeValue(value: any, key?: any): any {
  * and takes care of Error objects serialization
  */
 function serializer(options: { normalize: boolean } = { normalize: true }): (key: string, value: any) => any {
-  const stack: any[] = [];
-  const keys: string[] = [];
-
-  /** recursive */
-  function cycleserializer(_key: string, value: any): any {
-    if (stack[0] === value) {
-      return '[Circular ~]';
-    }
-    return `[Circular ~.${keys.slice(0, stack.indexOf(value)).join('.')}]`;
-  }
-
-  return function(this: any, key: string, value: any): any {
-    if (stack.length > 0) {
-      const thisPos = stack.indexOf(this);
-
-      if (thisPos === -1) {
-        stack.push(this);
-        keys.push(key);
-      } else {
-        stack.splice(thisPos + 1);
-        keys.splice(thisPos, Infinity, key);
-      }
-
-      if (stack.indexOf(value) !== -1) {
-        // tslint:disable-next-line:no-parameter-reassignment
-        value = cycleserializer.call(this, key, value);
-      }
-    } else {
-      stack.push(value);
-    }
-
-    return options.normalize ? normalizeValue(value, key) : value;
-  };
+  // tslint:disable-next-line
+  return (key: string, value: object) => (options.normalize ? normalizeValue(decycle(value), key) : decycle(value));
 }
 
 /**

packages/utils/test/object.test.ts

@@ -53,7 +53,7 @@ describe('serialize()', () => {
       expect(serialize(obj)).toEqual(
         JSON.stringify({
           name: 'Alice',
-          child: { name: 'Bob', self: '[Circular ~.child]' },
+          child: { name: 'Bob', self: '[Circular ~]' },
         }),
       );
     });
@@ -65,7 +65,7 @@ describe('serialize()', () => {
       expect(serialize(obj)).toEqual(
         JSON.stringify({
           name: 'Alice',
-          child: { name: 'Bob', identity: { self: '[Circular ~.child]' } },
+          child: { name: 'Bob', identity: { self: '[Circular ~]' } },
         }),
       );
     });
@@ -94,10 +94,7 @@ describe('serialize()', () => {
       expect(serialize(obj)).toEqual(
         JSON.stringify({
           name: 'Alice',
-          children: [
-            { name: 'Bob', self: '[Circular ~.children.0]' },
-            { name: 'Eve', self: '[Circular ~.children.1]' },
-          ],
+          children: [{ name: 'Bob', self: '[Circular ~]' }, { name: 'Eve', self: '[Circular ~]' }],
         }),
       );
     });
@@ -310,7 +307,7 @@ describe('safeNormalize()', () => {
       obj.child.self = obj.child;
       expect(safeNormalize(obj)).toEqual({
         name: 'Alice',
-        child: { name: 'Bob', self: '[Circular ~.child]' },
+        child: { name: 'Bob', self: '[Circular ~]' },
       });
     });
 
@@ -320,7 +317,7 @@ describe('safeNormalize()', () => {
       obj.child.identity = { self: obj.child };
       expect(safeNormalize(obj)).toEqual({
         name: 'Alice',
-        child: { name: 'Bob', identity: { self: '[Circular ~.child]' } },
+        child: { name: 'Bob', identity: { self: '[Circular ~]' } },
       });
     });
 
@@ -345,7 +342,7 @@ describe('safeNormalize()', () => {
       obj.children[1].self = obj.children[1];
       expect(safeNormalize(obj)).toEqual({
         name: 'Alice',
-        children: [{ name: 'Bob', self: '[Circular ~.children.0]' }, { name: 'Eve', self: '[Circular ~.children.1]' }],
+        children: [{ name: 'Bob', self: '[Circular ~]' }, { name: 'Eve', self: '[Circular ~]' }],
       });
     });