1 files changed, 85 insertions, 0 deletions
diff --git a/ext/js/core/extension-error.js b/ext/js/core/extension-error.js
new file mode 100644
index 00000000..f1485a74
--- /dev/null
+++ b/ext/js/core/extension-error.js
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Custom error class for the extension which can contain extra data.
+ * This works around an issue where assigning the `DOMException.data` field can fail on Firefox.
+ * @see https://bugzilla.mozilla.org/show_bug.cgi?id=1776555
+ */
+export class ExtensionError extends Error {
+    /**
+     * @param {string} message
+     */
+    constructor(message) {
+        super(message);
+        /** @type {unknown} */
+        this._data = void 0;
+    }
+
+    /** @type {unknown} */
+    get data() { return this._data; }
+    set data(value) { this._data = value; }
+
+    /**
+     * Converts an `Error` object to a serializable JSON object.
+     * @param {unknown} error An error object to convert.
+     * @returns {import('core').SerializedError} A simple object which can be serialized by `JSON.stringify()`.
+     */
+    static serialize(error) {
+        try {
+            if (typeof error === 'object' && error !== null) {
+                const {name, message, stack} = /** @type {import('core').SerializableObject} */ (error);
+                /** @type {import('core').SerializedError1} */
+                const result = {
+                    name: typeof name === 'string' ? name : '',
+                    message: typeof message === 'string' ? message : '',
+                    stack: typeof stack === 'string' ? stack : ''
+                };
+                if (error instanceof ExtensionError) {
+                    result.data = error.data;
+                }
+                return result;
+            }
+        } catch (e) {
+            // NOP
+        }
+        return /** @type {import('core').SerializedError2} */ ({
+            value: error,
+            hasValue: true
+        });
+    }
+
+    /**
+     * Converts a serialized error into a standard `Error` object.
+     * @param {import('core').SerializedError} serializedError A simple object which was initially generated by the `serialize` function.
+     * @returns {ExtensionError} A new `Error` instance.
+     */
+    static deserialize(serializedError) {
+        if (serializedError.hasValue) {
+            const {value} = serializedError;
+            return new ExtensionError(`Error of type ${typeof value}: ${value}`);
+        }
+        const {message, name, stack, data} = serializedError;
+        const error = new ExtensionError(message);
+        error.name = name;
+        error.stack = stack;
+        if (typeof data !== 'undefined') {
+            error.data = data;
+        }
+        return error;
+    }
+}