Change logger to serialize errors

package.json

@@ -28,6 +28,7 @@
   "license": "MIT",
   "devDependencies": {
     "@types/callsites": "^3.0.0",
+    "@types/clone": "^2.1.0",
     "@types/faker": "^4.1.12",
     "@types/jest": "^26.0.13",
     "@types/json-stringify-safe": "^5.0.0",
@@ -52,7 +53,9 @@
   },
   "dependencies": {
     "callsites": "^3.1.0",
-    "json-stringify-safe": "^5.0.1"
+    "clone": "^2.1.2",
+    "json-stringify-safe": "^5.0.1",
+    "serialize-error": "^7.0.1"
   },
   "description": "The simplest json logger. Include typescript definitions.",
   "repository": {

src/logger-filter.ts

@@ -1,4 +1,6 @@
+import clone from "clone";
 import stringify from "json-stringify-safe";
+import { serializeError } from "serialize-error";
 import { DEFAULT_BLACK_LIST } from "./default-black-list";
 
 type TItem = { [key: string]: any };
@@ -27,8 +29,12 @@ export class LoggerFilter {
   }
 
   private filterObject(item: TItem): TItem {
+    const objectWithoutCircularReference = JSON.parse(stringify(item));
     Object.keys(item).forEach((key: string): void => {
-      item[key] = this.filterItem(key, item[key]);
+      const innerObject = this.isPlainObject(item[key])
+        ? objectWithoutCircularReference[key]
+        : item[key];
+      item[key] = this.filterItem(key, innerObject);
     });
 
     return item;
@@ -39,6 +45,10 @@ export class LoggerFilter {
       return this.placeholder;
     }
 
+    if (item instanceof Error) {
+      return serializeError(item);
+    }
+
     if (this.isPlainObject(item)) {
       return this.filterObject(item);
     }
@@ -55,7 +65,7 @@ export class LoggerFilter {
   }
 
   private clone(item: object): object {
-    return JSON.parse(stringify(item));
+    return clone(item);
   }
 
   private isOnBlacklist(key: string): boolean {

test/logger-filter.spec.ts

@@ -200,6 +200,26 @@ describe("LoggerFilter", () => {
     expect(parsed).toStrictEqual(expectedResult);
   });
 
+  it("Should serialize an error", () => {
+    // Given
+    const error = new Error("My internal error");
+    const item = { error };
+    const expectedResult = {
+      error: {
+        message: "My internal error",
+        name: "Error",
+      },
+    };
+    const filter = new LoggerFilter();
+
+    // When
+    const parsed: any = filter.process(item);
+
+    // Then
+    expect(parsed.error.message).toBe(expectedResult.error.message);
+    expect(parsed.error.name).toBe(expectedResult.error.name);
+  });
+
   it("Should replace an item value when it is an array of string", () => {
     // Given
     const key = faker.random.arrayElement(DEFAULT_BLACK_LIST);