Local variables in Koa.js context with Marko.js templating engin. + fs.watch for marko/hot-reload. Version1.

markserver.js

//var chokidar=require('chokidar');=> alas, it will not work. Just I don't know how
var koa=require('koa');
var path=require('path');
var serve=require('koa-static');
var Router=require('koa-router');
var fs=require('fs');
var viewsDir=path.join(__dirname,'templates');
require('marko/node-require').install();
var marko=require('marko');
require('marko/hot-reload').enable();
require('fs').watch(viewsDir,function(event,pat){
console.log(event,pat);
if(/\.marko$/.test(pat)){
var templpath=path.join(viewsDir,pat);
require('marko/hot-reload').handleFileModified(templpath);//magic with actually reloading 
}

});
function  marki(app,settings){
	if(app.context.stream){return;}
	var settings=settings || {};
	function *stream(view,ops){
		console.log('viewPath :',view)
                console.log
('ops :',ops)	var temp=marko.load(require.resolve(`./templates/${view}`));
		var fn=temp.stream(ops);
		return fn;
	}
	app.context.stream=function *(view,_context){
		var context = {};
		//here is a magik with globals variables
    merge(context, this.state);
    merge(context, _context);
    //I don't know is it correct for a stream yield * stream?
    var html = yield *stream(view, context);
	return html;
	}
}

var app=koa();
app.use(serve(__dirname+'/public'));
//marko.js middleware. I don't know marko's settings :(
marki(app,{});
//here context.state middleware(this.state) for throu routes globally and on a template site
//in hello-world.marko => ${data.admin} => Bobik
app.use(function *(next){
this.state.admin="Bobik";
yield next;})

var router=new Router();
//var template=marko.load(require.resolve('./templates/hello-world.marko'));
router.get('/',function *(){
//var das=template.stream({name:"Jura",who:this.state.admin});
var das= yield this.stream('hello-world.marko',{name:"Bobik",who:"I am"})
this.type='html';
this.body=das;
});

app.use(router.routes());


console.log(3000);
app.listen(process.env.PORT || 3000);

 function merge(target, source) {
  for (var key in source) {
    target[key] = source[key];
  }
}

this.state.admin is null, is nothing on includes and on a layout. Is it a bug? No idea.
There is the way. You should delegate global data via include, for example:
< include template="./main-menu.marko" menu="${data.admin}"/>
And in main-menu.marko => ${data.menu} => Bobik

Before var html need to write try catch block.