u-mongoose-expressapi/src/common/helpers/errorHandler.js

Common functions for Express and Mongoose API

const {Response} = require('./responseHandler')

const handleError = (res, error) => {
    if (error?.code === 11000) {
        return Response(res, 400, ErrorHandler2(error));
    } else {
        return Response(res, 400, ErrorHandler(error));
    }
};


const ErrorHandler = (err) => {
    return err.message? err.message.substring(err.message.lastIndexOf(":") + 1):"An Unexpected Error on server site"
}


const uniqueMessage = error => {
    console.log("uniqueMessage",error)
    let output;
    try {
        let fieldName = error.message.substring(error.message.lastIndexOf('.$') + 2, error.message.lastIndexOf('_1'));
        output = fieldName.charAt(0).toUpperCase() + fieldName.slice(1) + ' already exists';
    } catch (ex) {
        output = 'Unique field already exists';
    }

    return output;
};
const ErrorHandler2 = error => {
    let message = '';

    if (error.code) {
        switch (error.code) {
            case 11000:
            case 11001:
                message = uniqueMessage(error);
                break;
            default:
                message = 'Something went wrong';
        }
    } else {
        for (let errorName in error.errorors) {
            if (error.errorors[errorName].message) message = error.errorors[errorName].message;
        }
    }

    return message.substring(message.lastIndexOf(":") + 2);
};


module.exports = {
    ErrorHandler,
    ErrorHandler2,
    handleError
    // other exports if any
  };