1 files changed, 75 insertions, 0 deletions
diff --git a/packages/backend/src/misc/render-inline-error.ts b/packages/backend/src/misc/render-inline-error.ts
new file mode 100644
index 0000000000..07f9f3068e
--- /dev/null
+++ b/packages/backend/src/misc/render-inline-error.ts
@@ -0,0 +1,75 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { IdentifiableError } from '@/misc/identifiable-error.js';
+import { StatusError } from '@/misc/status-error.js';
+import { CaptchaError } from '@/core/CaptchaService.js';
+
+export function renderInlineError(err: unknown): string {
+	const parts: string[] = [];
+	renderTo(err, parts);
+	return parts.join('');
+}
+
+function renderTo(err: unknown, parts: string[]): void {
+	parts.push(printError(err));
+
+	if (err instanceof AggregateError) {
+		for (let i = 0; i < err.errors.length; i++) {
+			parts.push(` [${i + 1}/${err.errors.length}]: `);
+			renderTo(err.errors[i], parts);
+		}
+	}
+
+	if (err instanceof Error) {
+		if (err.cause) {
+			parts.push(' [caused by]: ');
+			renderTo(err.cause, parts);
+			// const cause = renderInlineError(err.cause);
+			// parts.push(' [caused by]: ', cause);
+		}
+	}
+}
+
+function printError(err: unknown): string {
+	if (err === undefined) return 'undefined';
+	if (err === null) return 'null';
+
+	if (err instanceof IdentifiableError) {
+		if (err.message) {
+			return `${err.name} ${err.id}: ${err.message}`;
+		} else {
+			return `${err.name} ${err.id}`;
+		}
+	}
+
+	if (err instanceof StatusError) {
+		if (err.message) {
+			return `${err.name} ${err.statusCode}: ${err.message}`;
+		} else if (err.statusMessage) {
+			return `${err.name} ${err.statusCode}: ${err.statusMessage}`;
+		} else {
+			return `${err.name} ${err.statusCode}`;
+		}
+	}
+
+	if (err instanceof CaptchaError) {
+		if (err.code.description) {
+			return `${err.name} ${err.code.description}: ${err.message}`;
+		} else {
+			return `${err.name}: ${err.message}`;
+		}
+	}
+
+	if (err instanceof Error) {
+		if (err.message) {
+			return `${err.name}: ${err.message}`;
+		} else {
+			return err.name;
+		}
+	}
+
+	return String(err);
+}