なんかもうめっちゃ変えた

packages/backend/src/misc/status-error.ts

@@ -0,0 +1,13 @@
+export class StatusError extends Error {
+	public statusCode: number;
+	public statusMessage?: string;
+	public isClientError: boolean;
+
+	constructor(message: string, statusCode: number, statusMessage?: string) {
+		super(message);
+		this.name = 'StatusError';
+		this.statusCode = statusCode;
+		this.statusMessage = statusMessage;
+		this.isClientError = typeof this.statusCode === 'number' && this.statusCode >= 400 && this.statusCode < 500;
+	}
+}