What is happening in new DynamicProperty( this.leftBarrierViewPointProperty ).lazyLink( resizeBarrier );?

[samreid]

During code review #5, I noticed:

new DynamicProperty( this.leftBarrierViewPointProperty ).lazyLink( resizeBarrier );

How is this different from

this.leftBarrierViewPointProperty.lazyLink( resizeBarrier );

I saw a total of 3 DynamicProperty instantiations this applies to.

[jonathanolson]

leftBarrierViewPointProperty/rightBarrierViewPointProperty are Properties of Properties, and we need to also listen to the secondary Property for updates. Should those fields be renamed to something with ...PropertyProperty to better indicate that?

[samreid]

I don't understand why rightBarrierViewPointProperty should be a Property<Property>. Isn't it a constant value depending on the screen? For instance, BuoyancyExploreScreenView always has:

    this.rightBarrierViewPointProperty.value = new DerivedProperty( [ this.rightBox.boundsProperty, this.visibleBoundsProperty ], ( boxBounds, visibleBounds ) => {
      return new Vector2( boxBounds.left, visibleBounds.centerY );
    } )

Why is this designed to be dynamic?

[jonathanolson]

Why is this designed to be dynamic?

It's easier/simpler to design it that way, in my opinion. No fragility of "when after super() have we properly setup the Property so that NOW we can start to listen to it". Is there a better way?

[jonathanolson]

Isn't it a constant value depending on the screen?

It does eventually end up pointing to a specific Property depending on the screen, yes.

[samreid]

I noticed some places use value.value and some use DynamicProperty. Are all of those usages appropriate, or should some switch? For me and perhaps other developers, DynamicProperty.link may be more opaque than using value.value.

[samreid]

@jonathanolson and I discussed this, and thought the documentation was the best way to address this, closing.