@tdsoft/express-routing-wrapper/src/ApiMiddleware.js

Package gives you level of abstraction/wrapping of express router(s), endpoints and middlewares, additionally defining subrouters makes tree structure possible and easily discoverable by root router.

const logger = console; // temporary
const _ = require("lodash");
const createError = require("http-errors");

// TODO: Refactor most of the code to some Validation utils, etc.
// * prevalidate request
// * checkRequiredParams...

class ApiMiddleware {
    constructor({
                    access, method,
                    reqBody, reqCookies, reqDbModel, reqHeaders, reqPath, reqQuery,
                    resBody, resCookies, resDbModel
                },
                cb = () => logger.warn("Middleware has no cb provided!")) {
        this.def = {method};
        this.def.access = {...access};
        this.def.req = {body: reqBody, dbModel: reqDbModel, query: reqQuery, cookies: reqCookies, headers: reqHeaders, path: reqPath};
        this.def.res = {body: resBody, dbModel: resDbModel, cookies: resCookies};
        this.cb = cb;
    }

    async expressFn(req, res, next) {
        const credentials = await this._checkAccessRights(req, res, next);
        if (credentials.err) return;

        const errorMsgs = [
            ...this.checkBodyParams(req),
            ...this.checkQueryParams(req),
        ];
        if (errorMsgs.length) {
            next(createError.BadRequest(errorMsgs.join("</br>\n")));
        } else return this.cb(req, res, next)
            .catch(err => next(err));
    }

    async _checkAccessRights(req, res, next) {
        const {access} = this.def;
        if (access && access.level && access.cb) {
            return await access.cb(req, res, next, access.level);
        }
        return {};
    }

    _checkRequiredParams(reqAcess, paramsObj, paramsDesc = "") {
        const reqBodyFields = _.chain(paramsObj)
            .reduce((reducer, v, field) => [...reducer, (v.required && field)], [])
            .compact().value();
        //.map((v, key) => key);
        const notPassedFields = reqBodyFields.reduce((reducer, field) => (reqAcess[field]) ? reducer :
            [...reducer, `Passed${paramsDesc} parameters don't contain required "${field}" field.`], []);
        return notPassedFields;

    }

    checkBodyParams(req) {
        return this._checkRequiredParams(req.body, this.def.body, " body");
    }

    checkQueryParams(req) {
        return this._checkRequiredParams(req.query, this.def.query, " query");
    }
}

module.exports = ApiMiddleware;