Például ha Reactos projekte van az embernek, és használ JSX-et és reactify-al buildeli, akkor ezeket a harmony feature-öket használhatja:
reactify transform also can compile a limited set of es6 syntax constructs into es5. Supported features are arrow functions, rest params, templates, object short notation and classes. You can activate this via --es6 or --harmony boolean option:
Mozillában tesztelve, próbáldd ki őket, scratchpadben mindegyik megy 
arrow functions
============
document.body.addEventListener('click', event => console.log(event.target));
rest params
=========
function sum(a, b, ...rest) {
return Math.max(...[a,b].concat(rest));
}
console.log(sum(1,2)); // 2
console.log(sum(1,2,4,1,5,6,12,2,3)); // 12
templates
========
console.log(
`The max out of 1 and 2 is ${sum(1,2)}`
);
// "The max out of 1 and 2 is 2"
object shorthand notation
===================
var myModule = function() {
var newMax = function(a, b, ...rest) {
return Math.max(...[a,b].concat(rest));
};
var oldMax = function() {
return Math.max.apply(Math.max, [].slice.call(arguments));
};
// old syntax
// return {
// oldMax: oldMax,
// newMax: newMax
// };
return {
oldMax,
newMax
};
};
console.log(
myModule().oldMax(1,2,3,4,9,3,4,5)
); // 9
classes
======
// In iojs/node
class Topic extends EventEmitter {
constructor() {
super();
}
publish() {
this.emit('article');
}
subscribe(subscriber) {
// subscribe
}
}
És nincs felsorolva, de a destructuring is műküdik:
destructuring
==========
var React = require('react'),
{ Route, DefaultRoute } = require('react-router'),
{ AppComponent, Contact, Content } = require('./components/Screens'),
baseUrl = require('../appConfig.json').app.baseUrl;
module.exports = (
<Route name="home" path={baseUrl} handler={AppComponent}>
<Route name="contact" path="contact" handler={Contact} />
<DefaultRoute handler={Content} />
</Route>
);