From 0ef7b809aec24fc75f40242227a57fecf0ae9d28 Mon Sep 17 00:00:00 2001
From: Alberto Delgado Roda <albert.delgadoroda@elastic.co>
Date: Mon, 18 Sep 2023 16:24:24 +0200
Subject: [PATCH] feat(rum-core): stringify rejected obj

---
 .../src/error-logging/error-logging.js        | 40 ++++++++++++++-----
 .../test/error-logging/error-logging.spec.js  | 26 ++++++++++--
 packages/rum/src/index.js                     |  1 +
 3 files changed, 53 insertions(+), 14 deletions(-)

diff --git a/packages/rum-core/src/error-logging/error-logging.js b/packages/rum-core/src/error-logging/error-logging.js
index e149e516b..5f4a5ffc5 100644
--- a/packages/rum-core/src/error-logging/error-logging.js
+++ b/packages/rum-core/src/error-logging/error-logging.js
@@ -33,6 +33,7 @@ import stackParser from 'error-stack-parser'
  * List of keys to be ignored from getting added to custom error properties
  */
 const IGNORE_KEYS = ['stack', 'message']
+const PROMISE_REJECTION_PREFIX = 'Unhandled promise rejection: '
 
 function getErrorProperties(error) {
   /**
@@ -172,7 +173,6 @@ class ErrorLogging {
   }
 
   logPromiseEvent(promiseRejectionEvent) {
-    const prefix = 'Unhandled promise rejection: '
     let { reason } = promiseRejectionEvent
     if (reason == null) {
       reason = '<no reason specified>'
@@ -186,18 +186,10 @@ class ErrorLogging {
       const name = reason.name ? reason.name + ': ' : ''
       errorEvent = {
         error: reason,
-        message: prefix + name + reason.message
+        message: PROMISE_REJECTION_PREFIX + name + reason.message
       }
     } else {
-      reason =
-        typeof reason === 'object'
-          ? '<object>'
-          : typeof reason === 'function'
-          ? '<function>'
-          : reason
-      errorEvent = {
-        message: prefix + reason
-      }
+      errorEvent = this._parseRejectReason(reason)
     }
     this.logErrorEvent(errorEvent)
   }
@@ -211,6 +203,32 @@ class ErrorLogging {
     }
     return this.logErrorEvent(errorEvent)
   }
+
+  _parseRejectReason(reason) {
+    const errorEvent = {
+      message: PROMISE_REJECTION_PREFIX
+    }
+
+    if (Array.isArray(reason)) {
+      errorEvent.message += '<object>'
+    } else if (typeof reason === 'object') {
+      try {
+        errorEvent.message += JSON.stringify(reason)
+        errorEvent.error = reason
+      } catch (error) {
+        // fallback. JSON.stringify can throw exceptions in different circumstances.
+        // please, see this link for more info:
+        // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#exceptions
+        errorEvent.message += '<object>'
+      }
+    } else if (typeof reason === 'function') {
+      errorEvent.message += '<function>'
+    } else {
+      errorEvent.message += reason
+    }
+
+    return errorEvent
+  }
 }
 
 export default ErrorLogging
diff --git a/packages/rum-core/test/error-logging/error-logging.spec.js b/packages/rum-core/test/error-logging/error-logging.spec.js
index 6546210ea..758d78b46 100644
--- a/packages/rum-core/test/error-logging/error-logging.spec.js
+++ b/packages/rum-core/test/error-logging/error-logging.spec.js
@@ -393,24 +393,44 @@ describe('ErrorLogging', function () {
     )
 
     errorLogging.logPromiseEvent({
-      reason: [{ a: '1' }]
+      reason: ['array-value']
     })
     expect(getEvents()[7][ERRORS].exception.message).toBe(
       'Unhandled promise rejection: <object>'
     )
 
+    errorLogging.logPromiseEvent({
+      reason: { a: '1' }
+    })
+    expect(getEvents()[8][ERRORS].exception.message).toBe(
+      'Unhandled promise rejection: {"a":"1"}'
+    )
+
+    // Make sure that the object fallback case works
+    // Circular objects causes JSON.stringify to fail
+    const circularObj = {
+      foo: 'bar'
+    }
+    circularObj.self = circularObj
+    errorLogging.logPromiseEvent({
+      reason: circularObj
+    })
+    expect(getEvents()[9][ERRORS].exception.message).toBe(
+      'Unhandled promise rejection: <object>'
+    )
+
     const noop = function () {}
     errorLogging.logPromiseEvent({
       reason: noop
     })
-    expect(getEvents()[8][ERRORS].exception.message).toBe(
+    expect(getEvents()[10][ERRORS].exception.message).toBe(
       'Unhandled promise rejection: <function>'
     )
 
     errorLogging.logPromiseEvent({
       reason: null
     })
-    expect(getEvents()[9][ERRORS].exception.message).toBe(
+    expect(getEvents()[11][ERRORS].exception.message).toBe(
       'Unhandled promise rejection: <no reason specified>'
     )
 
diff --git a/packages/rum/src/index.js b/packages/rum/src/index.js
index 1f39bfe96..db501fb49 100644
--- a/packages/rum/src/index.js
+++ b/packages/rum/src/index.js
@@ -50,6 +50,7 @@ function getApmBase() {
 }
 
 const apmBase = getApmBase()
+
 const init = apmBase.init.bind(apmBase)
 
 export default init