Install joi

• https://www.npmjs.com/package/joi ( ~2M weekly downloads)

    npm i joi

Create SchemaValidator

    const Joi = require('joi');

    const options = {
        abortEarly: false, // include all errors
        allowUnknown: true, // ignore unknown props
        stripUnknown: true // remove unknown props
    };

    class UserSchemaValidator {

        createUserSchema = async function (req,res,next){
            const schema = Joi.object({
                name: Joi.string().required(),
                email: Joi.string().email().required(),
                password: Joi.string().min(6).required(),
                role: Joi.string().valid('ADMIN', 'USER').required()
            });

            validate(schema,req,res,next);
        }

        validate = async function(schema,req,res,next){
            try{
                let result = await schema.validateAsync(req.body, options);
                console.log("Result:", result);
                //validateRequest(req,next, schema);
                next();
            }
            catch(error){    
                let errorMessages = error.details.map(x=>x.message);       
                console.error(JSON.stringify(errorMessages));
                let result = { status: 400, errors: errorMessages};
                res.status(400).json(result);
            }
        }

    }

    exports.UserSchemaValidator = UserSchemaValidator;