demo of how middleware could be implemented with async/await

middleware-with-async.js

(async () => {
    class Application {
        constructor() {
            this.middlewares = [];
        }
        use(func) {
            this.middlewares.splice(0, 0, func);
        }
        async execute() {
            await this.middlewares.reduce((a, b) => {
                return async () => b(a);
            }, async () => { })();
        }
    }

    var app = new Application();
    var m1 = async function (next) {
        var start = new Date;
        console.log("m1 executing");
        await next();
        var ms = new Date - start;
        console.log(`m1 executed in ${ms}ms`);
    }
    app.use(m1);

    var m2 = async function (next) {
        var start = new Date;
        console.log("m2 executing");
        await next();
        var ms = new Date - start;
        console.log(`m2 executed in ${ms}ms`);
    };
    app.use(m2);

    var m3 = async function (next) {
        var start = new Date;
        console.log("m3 executing");
        await next();
        var ms = new Date - start;
        console.log(`m3 executed in ${ms}ms`);
    };
    app.use(m3);

    var m4 = async function (next) {
        var start = new Date;
        console.log("m4 executing");
        await next();
        var ms = new Date - start;
        console.log(`m4 executed in ${ms}ms`);
    };
    app.use(m4);

    var m5 = async function (next) {
        var start = new Date;
        console.log("m5 executing");
        await next();
        var waitTill = new Date(new Date().getTime() + 3 * 1000);
        while (waitTill > new Date()) { }
        var ms = new Date - start;
        console.log(`m5 executed in ${ms}ms`);
    };
    app.use(m5);

    await app.execute();
    console.log("the end");
})();