The simplest service strictifier ever

ed.js

import Joi from 'joi';
import _ from 'lodash';

import {
  BadRequestError
} from './errors';

const _promisedValidate = (msg, schema) => {
  return new Promise((resolve, reject) => {
    Joi.validate(msg, schema, {
      stripUnknown: true
    }, (err, value) => {
      if (err) {
        reject(new BadRequestError(err.details[0].message, err.details[0].path));
      } else {
        resolve(value);
      }
    });
  });
};

const optsSchema = Joi.object().keys({
  reqSchema: Joi.object().required(),
  resSchema: Joi.object().required(),
  handler: Joi.func().required()
});


export default (opts) => {
  const result = Joi.validate(opts, optsSchema);

  if (result.error) {
    throw error;
  }

  const o = result.value;

  return (req, res, next) => {
    const reqContent = _.extend({}, req.body, req.query, req.params);

    const ctx = {req, res};

    _promisedValidate(reqContent, o.reqSchema)
      .then((reqMsg) => {
        return o.handler(reqMsg, ctx);
      })
      .then((resMsg) => {
        return _promisedValidate(resMsg, o.resSchema);
      })
      .then((data) => {
        res.json(data);
      })
      .catch((err) => {
        next(err);
      });
  };
};