Minor documentation and initialize primitives at declaration, see #123

js/buoyancy/model/Boat.ts

@@ -34,16 +34,18 @@ export default class Boat extends ApplicationsMass {
 
   // The volume that the boat can hold inside it.
   public readonly liquidMaterialProperty: TProperty<Material>;
+
+  // The interior that can contain liquid
   public readonly basin: BoatBasin;
 
   // Amount of volume contained in the basin
-  public stepInternalVolume: number;
+  public stepInternalVolume = 0;
 
   // How to multiply our one-liter boat shape up to the model coordinates, since the boat changes size based on its
   // volume. This is much preferred to trying to redraw the shape to a different size.
-  public stepMultiplier: number;
+  public stepMultiplier = 0;
 
-  // Wether the boat is underwater or not
+  // Whether the boat is underwater (at all) or not. Does not need to be fully submerged.
   public isUnderwater = false;
 
   public constructor( engine: PhysicsEngine, blockWidthProperty: TReadOnlyProperty<number>, liquidMaterialProperty: TProperty<Material>, providedOptions: BoatOptions ) {
@@ -97,15 +99,10 @@ export default class Boat extends ApplicationsMass {
 
     this.basin = new BoatBasin( this );
 
-    this.stepInternalVolume = 0;
-    this.stepMultiplier = 0;
     Multilink.multilink( [ this.liquidMaterialProperty, this.basin.liquidVolumeProperty ], ( material, volume ) => {
       this.containedMassProperty.value = material.density * volume;
     } );
 
-    this.stepInternalVolume = 0;
-    this.stepMultiplier = 0;
-
     const intersectionMesh = new THREE.Mesh( BoatDesign.getPrimaryGeometry( 1 ), new THREE.MeshLambertMaterial() );
     this.intersectionGroup.add( intersectionMesh );
 

js/common/model/Mass.ts

@@ -175,10 +175,10 @@ export default abstract class Mass extends PhetioObject {
   public readonly customColorProperty?: Property<Color>;
 
   // Whether we are modifying the volumeProperty directly
-  protected volumeLock: boolean;
+  protected volumeLock = false;
 
   // Whether we are modifying the massProperty directly
-  protected massLock: boolean;
+  protected massLock = false;
 
   // In m^3 (cubic meters)
   public readonly volumeProperty: NumberProperty;
@@ -377,8 +377,6 @@ export default abstract class Mass extends PhetioObject {
       } );
     }
 
-    this.volumeLock = false;
-
     this.volumeProperty = new NumberProperty( options.volume, combineOptions<NumberPropertyOptions>( {
       tandem: tandem?.createTandem( 'volumeProperty' ),
       range: new Range( options.minVolume, options.maxVolume ),
@@ -398,8 +396,6 @@ export default abstract class Mass extends PhetioObject {
       tandem: Tandem.OPT_OUT
     } );
 
-    this.massLock = false;
-
     this.massProperty = new GuardedNumberProperty( this.materialProperty.value.density * this.volumeProperty.value + this.containedMassProperty.value, combineOptions<GuardedNumberPropertyOptions>( {
       tandem: tandem?.createTandem( 'massProperty' ),
       phetioReadOnly: true,