LibWeb/HTML: Extract ErrorInformation struct into its own files

This is used from a few different places in the spec.

Author: AtkinsSJ

Libraries/LibWeb/CMakeLists.txt

@@ -474,6 +474,7 @@ set(SOURCES
     HTML/ElementInternals.cpp
     HTML/EmbedderPolicy.cpp
     HTML/ErrorEvent.cpp
+    HTML/ErrorInformation.cpp
     HTML/EventHandler.cpp
     HTML/EventLoop/EventLoop.cpp
     HTML/EventLoop/Task.cpp

Libraries/LibWeb/HTML/ErrorInformation.cpp

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2025, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/VM.h>
+#include <LibWeb/HTML/ErrorInformation.h>
+
+namespace Web::HTML {
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#extract-error
+ErrorInformation extract_error_information(JS::VM& vm, JS::Value exception)
+{
+    // 1. Let attributes be an empty map keyed by IDL attributes.
+    ErrorInformation attributes;
+
+    // 2. Set attributes[error] to exception.
+    attributes.error = exception;
+
+    // 3. Set attributes[message], attributes[filename], attributes[lineno], and attributes[colno] to
+    //    implementation-defined values derived from exception.
+    attributes.message = [&] {
+        if (exception.is_object()) {
+            auto& object = exception.as_object();
+            if (MUST(object.has_own_property(vm.names.message))) {
+                auto message = object.get_without_side_effects(vm.names.message);
+                return message.to_string_without_side_effects();
+            }
+        }
+
+        return MUST(String::formatted("Uncaught exception: {}", exception.to_string_without_side_effects()));
+    }();
+
+    // FIXME: This offset is relative to the javascript source. Other browsers appear to do it relative
+    //        to the entire source document! Calculate that somehow.
+
+    // NB: If we got an Error object, then try and extract the information from the location the object was made.
+    if (exception.is_object() && is<JS::Error>(exception.as_object())) {
+        auto const& error = static_cast<JS::Error&>(exception.as_object());
+        for (auto const& frame : error.traceback()) {
+            auto source_range = frame.source_range();
+            if (source_range.start.line != 0 || source_range.start.column != 0) {
+                attributes.filename = MUST(String::from_byte_string(source_range.filename()));
+                attributes.lineno = source_range.start.line;
+                attributes.colno = source_range.start.column;
+                break;
+            }
+        }
+    }
+    // NB: Otherwise, we fall back to try and find the location of the invocation of the function itself.
+    else {
+        for (ssize_t i = vm.execution_context_stack().size() - 1; i >= 0; --i) {
+            auto& frame = vm.execution_context_stack()[i];
+            if (frame->executable) {
+                auto source_range = frame->executable->source_range_at(frame->program_counter).realize();
+                attributes.filename = MUST(String::from_byte_string(source_range.filename()));
+                attributes.lineno = source_range.start.line;
+                attributes.colno = source_range.start.column;
+                break;
+            }
+        }
+    }
+
+    // 4. Return attributes.
+    return attributes;
+}
+
+}

Libraries/LibWeb/HTML/ErrorInformation.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2025, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/Value.h>
+
+namespace Web::HTML {
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#extract-error
+struct ErrorInformation {
+    String message;
+    String filename;
+    JS::Value error;
+    size_t lineno { 0 };
+    size_t colno { 0 };
+};
+
+ErrorInformation extract_error_information(JS::VM&, JS::Value exception);
+
+}

Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.cpp

@@ -24,6 +24,7 @@
 #include <LibWeb/Fetch/FetchMethod.h>
 #include <LibWeb/HTML/CanvasRenderingContext2D.h>
 #include <LibWeb/HTML/ErrorEvent.h>
+#include <LibWeb/HTML/ErrorInformation.h>
 #include <LibWeb/HTML/EventLoop/EventLoop.h>
 #include <LibWeb/HTML/EventSource.h>
 #include <LibWeb/HTML/HTMLImageElement.h>
@@ -1151,72 +1152,6 @@ void WindowOrWorkerGlobalScopeMixin::report_error(JS::Value e)
     report_an_exception(e);
 }
 
-// https://html.spec.whatwg.org/multipage/webappapis.html#extract-error
-struct ErrorInformation {
-    String message;
-    String filename;
-    JS::Value error;
-    size_t lineno { 0 };
-    size_t colno { 0 };
-};
-
-// https://html.spec.whatwg.org/multipage/webappapis.html#extract-error
-static ErrorInformation extract_error_information(JS::VM& vm, JS::Value exception)
-{
-    // 1. Let attributes be an empty map keyed by IDL attributes.
-    ErrorInformation attributes;
-
-    // 2. Set attributes[error] to exception.
-    attributes.error = exception;
-
-    // 3. Set attributes[message], attributes[filename], attributes[lineno], and attributes[colno] to
-    //    implementation-defined values derived from exception.
-    attributes.message = [&] {
-        if (exception.is_object()) {
-            auto& object = exception.as_object();
-            if (MUST(object.has_own_property(vm.names.message))) {
-                auto message = object.get_without_side_effects(vm.names.message);
-                return message.to_string_without_side_effects();
-            }
-        }
-
-        return MUST(String::formatted("Uncaught exception: {}", exception.to_string_without_side_effects()));
-    }();
-
-    // FIXME: This offset is relative to the javascript source. Other browsers appear to do it relative
-    //        to the entire source document! Calculate that somehow.
-
-    // If we got an Error object, then try and extract the information from the location the object was made.
-    if (exception.is_object() && is<JS::Error>(exception.as_object())) {
-        auto const& error = static_cast<JS::Error&>(exception.as_object());
-        for (auto const& frame : error.traceback()) {
-            auto source_range = frame.source_range();
-            if (source_range.start.line != 0 || source_range.start.column != 0) {
-                attributes.filename = MUST(String::from_byte_string(source_range.filename()));
-                attributes.lineno = source_range.start.line;
-                attributes.colno = source_range.start.column;
-                break;
-            }
-        }
-    }
-    // Otherwise, we fall back to try and find the location of the invocation of the function itself.
-    else {
-        for (ssize_t i = vm.execution_context_stack().size() - 1; i >= 0; --i) {
-            auto& frame = vm.execution_context_stack()[i];
-            if (frame->executable) {
-                auto source_range = frame->executable->source_range_at(frame->program_counter).realize();
-                attributes.filename = MUST(String::from_byte_string(source_range.filename()));
-                attributes.lineno = source_range.start.line;
-                attributes.colno = source_range.start.column;
-                break;
-            }
-        }
-    }
-
-    // 4. Return attributes.
-    return attributes;
-}
-
 // https://html.spec.whatwg.org/multipage/webappapis.html#report-an-exception
 void WindowOrWorkerGlobalScopeMixin::report_an_exception(JS::Value exception, OmitError omit_error)
 {