In JavaScript, we can exploit closure to create private variables. Like so:
function Constructor() {
var count = 0;
this.getCount = function() { return count; };
this.increment = function() { count++; };
<html> | |
<head> | |
<script src="https://unpkg.com/tone@13.4.9/build/Tone.js"></script> | |
<script src="sketch.js"></script> | |
</head> | |
<body> | |
<button id="playbutton"> | |
Play | |
</button> | |
</body> |
const float FACTOR = 1.05946; // One semitone | |
float freq = 440; | |
const int BUTTON_UP = 3; | |
const int BUTTON_DOWN = 4; | |
const int SPEAKER = 0; | |
bool up_pressed = false; | |
bool down_pressed = false; |
The entities in an application's domain model are defined in large part by their relationships between them. The basic three are one-to-one, one-to-many, and many-to-many, but additional invariants may be layered on top of these. In a traditional OOP style, entities are responsible for maintaining these invariants, via logic in their public mutator methods. I propose an alternative that I call the connector pattern. In the connector pattern, object relationships are created and destroyed (connected and disconnected) by a third object called a Connector.
While objects should be responsible for maintaining their own local invariants, relationships are not local. They encompass both objects involved in a relationship. As a result, mutator methods on both objects must enforce a shared invariant. If a Foo has many Bars, then Foo.addBar(Bar)
and Bar.setFoo(Foo)
should be equivalent operations. These two meth