266943 2023-12-30 18:51:05 -0800 Throwing an Error subclass includes constructor in stacktrace (unlike V8) 2025-08-31 07:43:24 -0700 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 jarred webkit-unassigned mark.lam webkit-bug-importer ysuzuki oldest_to_newest 2002320 0 jarred 2023-12-30 18:51:05 -0800 The following code: ```js class CustomError extends Error { constructor(message) { super(message); } } const error = new CustomError("uh-oh!"); throw error; ``` Prints the following in `jsc`: ``` Exception: Error: uh-oh! CustomError@throw.js:3:10 global code@throw.js:7:30 ``` The first line of the stack trace is `super(message)`, which is not what users want to see. They want to see where the the error was thrown, not the `super` call for the Error subclass. In Node.js/V8, this works as expected - the first line is the one which threw ``` throw error; ^ CustomError: uh-oh! at Object.<anonymous> (/Users/jarred/throw.js:7:15) at Module._compile (node:internal/modules/cjs/loader:1376:14) at Module._extensions..js (node:internal/modules/cjs/loader:1435:10) at Module.load (node:internal/modules/cjs/loader:1207:32) at Module._load (node:internal/modules/cjs/loader:1023:12) at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:135:12) at node:internal/main/run_main_module:28:49 Node.js v21.4.0 ``` Similarly, pasting the snippet into Chrome DevTools reports: ``` VM51:9 Uncaught Error: uh-oh! at <anonymous>:7:15 ``` Line 7 is the throw statement 2002533 1 webkit-bug-importer 2024-01-02 09:58:32 -0800 <rdar://problem/120375032> 2138433 2 sosuke 2025-08-22 23:35:49 -0700 Pull request: https://github.com/WebKit/WebKit/pull/49808 2139957 3 ews-feeder 2025-08-31 07:43:23 -0700 Committed 299375@main (70c384691cea): <https://commits.webkit.org/299375@main> Reviewed commits have been landed. Closing PR #49808 and removing active labels.