// default data

const obj = {

  first: 'John',

  last: 'Doe'

};

// let's listen for first and last name changes

defi.on(obj, 'change:first', () => console.log('First name is changed'));

defi.on(obj, 'change:last', () => console.log('Last name is changed'));

​

// we would like to re-calculate 'greeting' property every time when the name is changed

defi.calc(obj, 'greeting', ['first', 'last'], (first, last) => `Hello, ${first} ${last}`);

​

// and we want to set up a two-way data binding between the props and corresponding DOM nodes

defi.bindNode(obj, {

  first: '.first',

  last: '.last',

  greeting: '.greeting'

});

​

// just to make it accesible via console

window.obj = obj;