Passing Data Between Components Summary

In the above sections we have seen 2 ways to pass data between components using the bindToController options.

= to pass variables from the current component into the component.

& to register a callback for component to invoke (with data if necessary) in order to pass data out of the component.

= and & are the mechanism that allow our component to have a "public API".

Note, if the attribute name and the property of the component class match the name can be omitted. i.e instead of username: '=username' we can just write username: '=', with the same shortcut applying to &.