Dynamic middleware for Express

customMiddleware.js

/**
 * Apply custom middlewares to request
 * Usage:
 *     1- Identify that you require dynamic middlewares for your endpoint.
 *     2- assign each middleware to a variable and push it to an array
 *         const middlewares = [middleware1, middlware2];
 *     3- require this file with expected objects.
 *
 * Example:
 *     const middleware1 = require('some middleware file here');
 *     const middleware2 = require('another middleware file here');
 *
 *     const middlewares = [middleware1, middleware2];
 *
 *     function myCustomMiddlware(request, response, next){
 *         if(somethingCondition){
 *             return customMiddlware(middlwares, request, response, next);
 *         }
 *         return customMiddleware([middleware1], request, response, next);
 *     }
 */

'use strict';

const async = require('async');

/**
 * middlewares: array of middlewares like require('a middleware file path')
 * request: request object from express middleware
 * response: response object from express middleware
 * next: callback from express middleware
 */
function customMiddlewares(middlewares = [], request, response, next) {

    /**
     * Bind each middleware to current request|response object for the actual
     * request to the endpoint
     */
    let options = middlewares.map(item => item.bind(null, request, response));

    /**
     * Run each middleware defined and associated to current request, if any
     * error, it will be handled by the `next` callback, also, on success or
     * internally called `next` for each middleware, call the next one in a
     * sequence
     */
    return async.series(options, (error) => next(error));
}

module.exports = customMiddlewares;