basecontroller.ts

import {Document, Model} from 'mongoose';
import {Request, Response} from 'express';
import {MongoError} from '../../../../Desktop/codewithcause/node_modules/@types/mongodb';

export class BaseController<U extends Document, T extends Model<U>> {
    
    model: T;

    constructor(_model: T) {
        this.model = _model;
    }

    // Define Error Response and API Responses
    private static resolveErrorResponse(response: Response, message: string, statusCode: number): Response {
        return response.status(statusCode).json({
            status: statusCode,
            message
        });
    }

    private static resolveMongoErrorResponse(response: Response, error: MongoError = null): Response {
        return response.status(500).json({
            status: 500,
            mongoError: error.code,
            message: error.message,
            error: error.name
        });
    }

    async getAll(req: Request, res: Response): Promise<Response> {
        const result = await this.model.find().exec();

        if (result instanceof MongoError)
            return BaseController.resolveMongoErrorResponse(res, result);

        return res.status(res.statusCode).json({
            status: res.statusCode,
            result
        });
    };

    async getById(req: Request, res: Response): Promise<Response> {
        const id = req.params.id;

        if (!id)
            return BaseController.resolveErrorResponse(res, 'Paramater ID is missing', 400);

        const result = await this.model.findById(id).exec();

        if (result instanceof MongoError)
            return BaseController.resolveMongoErrorResponse(res, result);

        return res.status(res.statusCode).json({
            status: res.statusCode,
            result
        });
    }

    async create(req: Request, res: Response): Promise<Response> {
        const requestBody: U = {...req.body} as U;

        if (!requestBody)
            return BaseController.resolveErrorResponse(res, 'Parameters missing', 400);

        const result = await this.model.create(requestBody);

        if (result instanceof MongoError)
            return BaseController.resolveMongoErrorResponse(res, result);

        return res.status(res.statusCode).json({
            status: res.statusCode,
            result
        })
    }

    async update(req: Request, res: Response): Promise<Response> {
        const updatedBody: U = {...req.body} as U;
        const id = req.body.id;

        if (!id)
            return BaseController.resolveErrorResponse(res, 'Parameter ID is missing', 400);

        if (!updatedBody)
            return BaseController.resolveErrorResponse(res, 'Parameters missing', 400);

        const result = await this.model.findByIdAndUpdate(id, updatedBody).exec();

        if (result instanceof MongoError)
            return BaseController.resolveMongoErrorResponse(res, result);

        return res.status(res.statusCode).json({
            status: res.statusCode,
            result
        });
    }

    async delete(req: Request, res: Response): Promise<Response> {
        const id = req.body.id;

        if (!id)
            return BaseController.resolveErrorResponse(res, 'Parameter ID is missing', 400);

        const result = await this.model.findByIdAndRemove(id).exec();

        if (result instanceof MongoError)
            return BaseController.resolveMongoErrorResponse(res, result);

        return res.status(res.statusCode).json({
            status: res.statusCode,
            result
        });
    }
}