ChromeDevTools · szuend · Feb 3, 2026 · Feb 3, 2026
diff --git a/src/DevtoolsUtils.ts b/src/DevtoolsUtils.ts
@@ -236,14 +236,20 @@ export async function createStackTraceForConsoleMessage(
     _targetId(): string | undefined;
   };
   const rawStackTrace = message._rawStackTrace();
-  if (!rawStackTrace) {
-    return undefined;
+  if (rawStackTrace) {
+    return createStackTrace(devTools, rawStackTrace, message._targetId());
   }
+  return undefined;
+}
 
+export async function createStackTrace(
+  devTools: TargetUniverse,
+  rawStackTrace: Protocol.Runtime.StackTrace,
+  targetId: string | undefined,
+): Promise<DevTools.StackTrace.StackTrace.StackTrace> {
   const targetManager = devTools.universe.context.get(DevTools.TargetManager);
-  const messageTargetId = message._targetId();
-  const target = messageTargetId
-    ? targetManager.targetById(messageTargetId) || devTools.target
+  const target = targetId
+    ? targetManager.targetById(targetId) || devTools.target
     : devTools.target;
   const model = target.model(DevTools.DebuggerModel) as DevTools.DebuggerModel;
 

diff --git a/src/formatters/ConsoleFormatter.ts b/src/formatters/ConsoleFormatter.ts
@@ -6,8 +6,10 @@
 
 import {
   createStackTraceForConsoleMessage,
+  createStackTrace,
   type TargetUniverse,
 } from '../DevtoolsUtils.js';
+import type {UncaughtError} from '../PageCollector.js';
 import type * as DevTools from '../third_party/index.js';
 import type {ConsoleMessage} from '../third_party/index.js';
 
@@ -19,13 +21,13 @@ export interface ConsoleFormatterOptions {
 }
 
 export class ConsoleFormatter {
-  #msg: ConsoleMessage | Error;
+  #msg: ConsoleMessage | Error | UncaughtError;
   #resolvedArgs: unknown[] = [];
   #resolvedStackTrace?: DevTools.DevTools.StackTrace.StackTrace.StackTrace;
   #id?: number;
 
   private constructor(
-    msg: ConsoleMessage | Error,
+    msg: ConsoleMessage | Error | UncaughtError,
     options?: ConsoleFormatterOptions,
   ) {
     this.#msg = msg;
@@ -34,7 +36,7 @@ export class ConsoleFormatter {
   }
 
   static async from(
-    msg: ConsoleMessage | Error,
+    msg: ConsoleMessage | Error | UncaughtError,
     options?: ConsoleFormatterOptions,
   ): Promise<ConsoleFormatter> {
     const formatter = new ConsoleFormatter(msg, options);
@@ -44,27 +46,44 @@ export class ConsoleFormatter {
     return formatter;
   }
 
+  #isConsoleMessage(
+    msg: ConsoleMessage | Error | UncaughtError,
+  ): msg is ConsoleMessage {
+    // No `instanceof` as tests mock `ConsoleMessage`.
+    return 'args' in msg && typeof msg.args === 'function';
+  }
+
   async #loadDetailedData(devTools?: TargetUniverse): Promise<void> {
     if (this.#msg instanceof Error) {
       return;
     }
 
-    this.#resolvedArgs = await Promise.all(
-      this.#msg.args().map(async (arg, i) => {
-        try {
-          return await arg.jsonValue();
-        } catch {
-          return `<error: Argument ${i} is no longer available>`;
-        }
-      }),
-    );
+    if (this.#isConsoleMessage(this.#msg)) {
+      this.#resolvedArgs = await Promise.all(
+        this.#msg.args().map(async (arg, i) => {
+          try {
+            return await arg.jsonValue();
+          } catch {
+            return `<error: Argument ${i} is no longer available>`;
+          }
+        }),
+      );
+    }
 
     if (devTools) {
       try {
-        this.#resolvedStackTrace = await createStackTraceForConsoleMessage(
-          devTools,
-          this.#msg,
-        );
+        if (this.#isConsoleMessage(this.#msg)) {
+          this.#resolvedStackTrace = await createStackTraceForConsoleMessage(
+            devTools,
+            this.#msg,
+          );
+        } else if (this.#msg.stackTrace) {
+          this.#resolvedStackTrace = await createStackTrace(
+            devTools,
+            this.#msg.stackTrace,
+            this.#msg.targetId,
+          );
+        }
       } catch {
         // ignore
       }
@@ -75,10 +94,7 @@ export class ConsoleFormatter {
   toString(): string {
     const type = this.#getType();
     const text = this.#getText();
-    const argsCount =
-      this.#msg instanceof Error
-        ? 0
-        : this.#resolvedArgs.length || this.#msg.args().length;
+    const argsCount = this.#getArgsCount();
     const idPart = this.#id !== undefined ? `msgid=${this.#id} ` : '';
     return `${idPart}[${type}] ${text} (${argsCount} args)`;
   }
@@ -95,21 +111,21 @@ export class ConsoleFormatter {
   }
 
   #getType(): string {
-    if (this.#msg instanceof Error) {
+    if (!this.#isConsoleMessage(this.#msg)) {
       return 'error';
     }
     return this.#msg.type();
   }
 
   #getText(): string {
-    if (this.#msg instanceof Error) {
+    if (!this.#isConsoleMessage(this.#msg)) {
       return this.#msg.message;
     }
     return this.#msg.text();
   }
 
   #getArgs(): unknown[] {
-    if (this.#msg instanceof Error) {
+    if (!this.#isConsoleMessage(this.#msg)) {
       return [];
     }
     if (this.#resolvedArgs.length > 0) {
@@ -123,6 +139,13 @@ export class ConsoleFormatter {
     return [];
   }
 
+  #getArgsCount(): number {
+    if (!this.#isConsoleMessage(this.#msg)) {
+      return 0;
+    }
+    return this.#resolvedArgs.length || this.#msg.args().length;
+  }
+
   #formatArg(arg: unknown) {
     return typeof arg === 'object' ? JSON.stringify(arg) : String(arg);
   }
@@ -185,10 +208,7 @@ export class ConsoleFormatter {
     return {
       type: this.#getType(),
       text: this.#getText(),
-      argsCount:
-        this.#msg instanceof Error
-          ? 0
-          : this.#resolvedArgs.length || this.#msg.args().length,
+      argsCount: this.#getArgsCount(),
       id: this.#id,
     };
   }

diff --git a/tests/formatters/ConsoleFormatter.test.js.snapshot b/tests/formatters/ConsoleFormatter.test.js.snapshot
@@ -10,6 +10,10 @@ exports[`ConsoleFormatter > toString > formats a console.log message with one ar
 msgid=2 [log] Processing file: (1 args)
 `;
 
+exports[`ConsoleFormatter > toString > formats an UncaughtError 1`] = `
+msgid=4 [error] Uncaught TypeError: Cannot read properties of undefined (0 args)
+`;
+
 exports[`ConsoleFormatter > toStringDetailed > formats a console message with a stack trace 1`] = `
 ID: 5
 Message: log> Hello stack trace!
@@ -45,6 +49,16 @@ Message: log> Processing file:
 Arg #0: file.txt
 `;
 
+exports[`ConsoleFormatter > toStringDetailed > formats an UncaughtError with a stack trace 1`] = `
+ID: 7
+Message: error> Uncaught TypeError: Cannot read properties of undefined
+### Stack trace
+at foo (foo.ts:10:2)
+at bar (foo.ts:20:2)
+--- setTimeout -------------------------
+at schedule (util.ts:5:2)
+`;
+
 exports[`ConsoleFormatter > toStringDetailed > handles \"Execution context is not available\" error in args 1`] = `
 ID: 6
 Message: log> Processing file:

diff --git a/tests/formatters/ConsoleFormatter.test.ts b/tests/formatters/ConsoleFormatter.test.ts
@@ -8,6 +8,7 @@ import assert from 'node:assert';
 import {describe, it} from 'node:test';
 
 import {ConsoleFormatter} from '../../src/formatters/ConsoleFormatter.js';
+import {UncaughtError} from '../../src/PageCollector.js';
 import type {ConsoleMessage} from '../../src/third_party/index.js';
 import type {DevTools} from '../../src/third_party/index.js';
 
@@ -66,6 +67,18 @@ describe('ConsoleFormatter', () => {
       ).toString();
       t.assert.snapshot?.(result);
     });
+
+    it('formats an UncaughtError', async t => {
+      const error = new UncaughtError(
+        'Uncaught TypeError: Cannot read properties of undefined',
+        undefined,
+        '<mock target ID>',
+      );
+      const result = (
+        await ConsoleFormatter.from(error, {id: 4, fetchDetailedData: true})
+      ).toString();
+      t.assert.snapshot?.(result);
+    });
   });
 
   describe('toStringDetailed', () => {
@@ -184,6 +197,53 @@ describe('ConsoleFormatter', () => {
       t.assert.snapshot?.(result);
       assert.ok(result.includes('<error: Argument 0 is no longer available>'));
     });
+
+    it('formats an UncaughtError with a stack trace', async t => {
+      const stackTrace = {
+        syncFragment: {
+          frames: [
+            {
+              line: 10,
+              column: 2,
+              url: 'foo.ts',
+              name: 'foo',
+            },
+            {
+              line: 20,
+              column: 2,
+              url: 'foo.ts',
+              name: 'bar',
+            },
+          ],
+        },
+        asyncFragments: [
+          {
+            description: 'setTimeout',
+            frames: [
+              {
+                line: 5,
+                column: 2,
+                url: 'util.ts',
+                name: 'schedule',
+              },
+            ],
+          },
+        ],
+      } as unknown as DevTools.StackTrace.StackTrace.StackTrace;
+      const error = new UncaughtError(
+        'Uncaught TypeError: Cannot read properties of undefined',
+        undefined,
+        '<mock target ID>',
+      );
+
+      const result = (
+        await ConsoleFormatter.from(error, {
+          id: 7,
+          resolvedStackTraceForTesting: stackTrace,
+        })
+      ).toStringDetailed();
+      t.assert.snapshot?.(result);
+    });
   });
   describe('toJSON', () => {
     it('formats a console.log message', async () => {