feat: wip

packages/lib/errors/app-error.ts

@@ -0,0 +1,144 @@
+import { TRPCError } from '@trpc/server';
+import { z } from 'zod';
+
+import { TRPCClientError } from '@documenso/trpc/client';
+
+/**
+ * Generic application error codes.
+ */
+export enum AppErrorCode {
+  'ALREADY_EXISTS' = 'AlreadyExists',
+  'EXPIRED_CODE' = 'ExpiredCode',
+  'INVALID_BODY' = 'InvalidBody',
+  'INVALID_REQUEST' = 'InvalidRequest',
+  'NOT_FOUND' = 'NotFound',
+  'NOT_SETUP' = 'NotSetup',
+  'UNAUTHORIZED' = 'Unauthorized',
+  'UNKNOWN_ERROR' = 'UnknownError',
+  'RETRY_EXCEPTION' = 'RetryException',
+  'SCHEMA_FAILED' = 'SchemaFailed',
+  'TOO_MANY_REQUESTS' = 'TooManyRequests',
+}
+
+const genericErrorCodeToTrpcErrorCodeMap: Record<string, TRPCError['code']> = {
+  [AppErrorCode.ALREADY_EXISTS]: 'BAD_REQUEST',
+  [AppErrorCode.EXPIRED_CODE]: 'BAD_REQUEST',
+  [AppErrorCode.INVALID_BODY]: 'BAD_REQUEST',
+  [AppErrorCode.INVALID_REQUEST]: 'BAD_REQUEST',
+  [AppErrorCode.NOT_FOUND]: 'NOT_FOUND',
+  [AppErrorCode.NOT_SETUP]: 'BAD_REQUEST',
+  [AppErrorCode.UNAUTHORIZED]: 'UNAUTHORIZED',
+  [AppErrorCode.UNKNOWN_ERROR]: 'INTERNAL_SERVER_ERROR',
+  [AppErrorCode.RETRY_EXCEPTION]: 'INTERNAL_SERVER_ERROR',
+  [AppErrorCode.SCHEMA_FAILED]: 'INTERNAL_SERVER_ERROR',
+  [AppErrorCode.TOO_MANY_REQUESTS]: 'TOO_MANY_REQUESTS',
+};
+
+export const ZAppErrorJsonSchema = z.object({
+  code: z.string(),
+  message: z.string().optional(),
+  userMessage: z.string().optional(),
+});
+
+export type TAppErrorJsonSchema = z.infer<typeof ZAppErrorJsonSchema>;
+
+export class AppError extends Error {
+  /**
+   * The error code.
+   */
+  code: string;
+
+  /**
+   * An error message which can be displayed to the user.
+   */
+  userMessage?: string;
+
+  /**
+   * Create a new AppError.
+   *
+   * @param errorCode A string representing the error code.
+   * @param message An internal error message.
+   * @param userMessage A error message which can be displayed to the user.
+   */
+  public constructor(errorCode: string, message?: string, userMessage?: string) {
+    super(message || errorCode);
+    this.code = errorCode;
+    this.userMessage = userMessage;
+  }
+
+  /**
+   * Parse an unknown value into an AppError.
+   *
+   * @param error An unknown type.
+   */
+  static parseError(error: unknown): AppError {
+    if (error instanceof AppError) {
+      return error;
+    }
+
+    // Handle TRPC errors.
+    if (error instanceof TRPCClientError) {
+      const parsedJsonError = AppError.parseFromJSONString(error.message);
+      return parsedJsonError || new AppError('UnknownError', error.message);
+    }
+
+    // Handle completely unknown errors.
+    // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
+    const { code, message, userMessage } = error as {
+      code: unknown;
+      message: unknown;
+      status: unknown;
+      userMessage: unknown;
+    };
+
+    const validCode: string | null = typeof code === 'string' ? code : AppErrorCode.UNKNOWN_ERROR;
+    const validMessage: string | undefined = typeof message === 'string' ? message : undefined;
+    const validUserMessage: string | undefined =
+      typeof userMessage === 'string' ? userMessage : undefined;
+
+    return new AppError(validCode, validMessage, validUserMessage);
+  }
+
+  static parseErrorToTRPCError(error: unknown): TRPCError {
+    const appError = AppError.parseError(error);
+
+    return new TRPCError({
+      code: genericErrorCodeToTrpcErrorCodeMap[appError.code] || 'BAD_REQUEST',
+      message: AppError.toJSONString(appError),
+    });
+  }
+
+  /**
+   * Convert an AppError into a JSON object which represents the error.
+   *
+   * @param appError The AppError to convert to JSON.
+   * @returns A JSON object representing the AppError.
+   */
+  static toJSON({ code, message, userMessage }: AppError): TAppErrorJsonSchema {
+    return {
+      code,
+      message,
+      userMessage,
+    };
+  }
+
+  /**
+   * Convert an AppError into a JSON string containing the relevant information.
+   *
+   * @param appError The AppError to stringify.
+   * @returns A JSON string representing the AppError.
+   */
+  static toJSONString(appError: AppError): string {
+    return JSON.stringify(AppError.toJSON(appError));
+  }
+
+  static parseFromJSONString(jsonString: string): AppError | null {
+    const parsed = ZAppErrorJsonSchema.safeParse(JSON.parse(jsonString));
+
+    if (!parsed.success) {
+      return null;
+    }
+
+    return new AppError(parsed.data.code, parsed.data.message, parsed.data.userMessage);
+  }
+}