README.md:

async/await function(required babel)

use for koa2:

app.js:
    const angularProxy=require('koa-angular-proxy');
    app.use(angularProxy('./dist'))

'./dist' is your directory of angular2 project that the entry file is index.html.

And suche use:

app.js:             
    app.use(mount('/router',angularProxy('./dist')));
    
./dist/index.html:  
    <base href='/router/'>