How to disenchant the magic of ember.js?

Question

JavaScript

Greetings.
Another example from the ember.js documentation . The actual code is here . Purely mechanically, how this code works is clear, but a trace appears in an inquisitive mind. Questions:
1. How is the controller's isCompleted method (more precisely, computed property) called automatically when the state of the checked property of the input element changes, if there is no hint of this in the code itself? That is, how does the controller actually know when the state of the input element's checked property changes?
2. Where in the documentation is this behavior specified?
Thank you.

Answer 1

stackoverflow.com/questions/16971011/itemcontrolle...
The each loop creates a TodoController for each item. In an element, the checked=isCompleted input is exactly what a two-way data binding is.

Answer 2

disenchant, bewilder

Answer 3

Nothing but to read the source can not advise.
And is there any other way to understand how "it" works?