pablo-rest-api-standard/src/index.ts

import type { Request, Response } from "express";

interface PRASResponse extends Response {
  pras: {
    ok: (message: string, data: any, code: string, extra: any) => void;
    created: (message: string, data: any, code: string, extra: any) => void;
    badRequest: (message: string, data: any, code: string, extra: any) => void;
    unauthorized: (
      message: string,
      data: any,
      code: string,
      extra: any
    ) => void;
    forbidden: (message: string, data: any, code: string, extra: any) => void;
    notFound: (message: string, data: any, code: string, extra: any) => void;
    serverError: (message: string, data: any, code: string, extra: any) => void;
    customMessage: (
      statusCode: number,
      message: string,
      data: any,
      code: string,
      extra: any
    ) => void;
  };
}

export class PRAS {
  private getPRASResultObject(
    statusCode = 200,
    status = "OK",
    message = "",
    data: any = null,
    code = "UNKNOWN_CODE",
    extra: any = null
  ): any {
    return {
      statusCode,
      status,
      message,
      data,
      code,
      extra,
    };
  }

  public responseMiddleware() {
    // eslint-disable-next-line @typescript-eslint/ban-types
    return (req: Request, res: PRASResponse, next: Function): void => {
      res.pras = {
        ok: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(200, "OK", message, data, code, extra)
          );
        },
        created: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(201, "OK", message, data, code, extra)
          );
        },
        badRequest: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(400, "FAIL", message, data, code, extra)
          );
        },
        unauthorized: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(401, "FAIL", message, data, code, extra)
          );
        },
        forbidden: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(403, "FAIL", message, data, code, extra)
          );
        },
        notFound: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(404, "FAIL", message, data, code, extra)
          );
        },
        serverError: (message, data, code, extra) => {
          res.json(
            this.getPRASResultObject(500, "ERROR", message, data, code, extra)
          );
        },
        customMessage: (statusCode, message, data, code, extra) => {
          let status;
          if (statusCode >= 500) {
            status = "ERROR";
          } else if (statusCode >= 400) {
            status = "FAIL";
          } else {
            status = "OK";
          }
          res.json(
            this.getPRASResultObject(
              statusCode,
              status,
              message,
              data,
              code,
              extra
            )
          );
        },
      };

      if (
        req.rawHeaders.hasOwnProperty("Accept") &&
        /application\/json/.test(req.rawHeaders["Accept"])
      ) {
        const send = res.send;
        res.send = (body) => {
          try {
            if (typeof body === "string") {
              body = JSON.parse(body);
            }
            if (typeof body === "string") {
              body = { data: body };
            } else if (!body.hasOwnProperty("data")) {
              body = { data: body };
            }
            const prasBody = this.getPRASResultObject(
              body.statusCode,
              body.status,
              body.message,
              body.data,
              body.code,
              body.extra
            );
            res.status(prasBody.statusCode || 200);
            delete prasBody.statusCode;
            return send.call(res, JSON.stringify(prasBody));
          } catch (err) {
            return send.call(res, body);
          }
        };
      }

      next();
    };
  }
}

export default new PRAS();