src/libs/bobject.js
function (key, target, targetKey, noNotify) {
        targetKey = targetKey || key;
        var self = this;
        this.unbind(key);

        var oldVal = this.get(key);

        // When bound property changes, trigger a 'changed' event on this one too
        getBindings(this)[key] = events.addListener(target, targetKey.toLowerCase() + '_changed', function (oldVal) {
            self.triggerChanged(key, oldVal);
        });

        addAccessor(this, key, target, targetKey, noNotify);
    }
function (key, target, targetKey, noNotify) {
        targetKey = targetKey || key;
        var self = this;
        this.unbind(key);

        var oldVal = this.get(key);

        // When bound property changes, trigger a 'changed' event on this one too
        getBindings(this)[key] = events.addListener(target, targetKey.toLowerCase() + '_changed', function (oldVal) {
            self.triggerChanged(key, oldVal);
        });

        addAccessor(this, key, target, targetKey, noNotify);
    }
function ( key , target , targetKey , noNotify ) { targetKey = targetKey || key ; var self = this ; this . unbind ( key ) ; var oldVal = this . get ( key ) ; // When bound property changes, trigger a 'changed' event on this one too getBindings ( this ) [ key ] = events . addListener ( target , targetKey . toLowerCase ( ) + '_changed' , function ( oldVal ) { self . triggerChanged ( key , oldVal ) ; } ) ; addAccessor ( this , key , target , targetKey , noNotify ) ; }
Bind the value of a property on this object to that of another object so
they always have the same value. Setting the value on either object will update
the other too.

@param {String} key Name of the property on this object that should be bound
@param {BOject} target Object to bind to
@param {String} [targetKey=key] Key on the target object to bind to
@param {Boolean} [noNotify=false] Set to true to prevent this object's property triggering a 'changed' event when adding the binding
Bind the value of a property on this object to that of another object so they always have the same value . Setting the value on either object will update the other too .