DynamicProperty field declarations that should be TReadOnlyProperty

[pixelzoom]

For code review #32 ...

There are many declarations of public fields of type DynamicProperty that should be TReadOnlyProperty. Search for ": DynamicProperty" and inspect them.

For example, in Field.ts:

-  public readonly meanSpeedProperty: DynamicProperty<number, number, Launcher>;
+  public readonly meanSpeedProperty: TReadOnlyProperty<number>;

In some cases, like SMField, this pattern should be used:

SMField patch

Subject: [PATCH] replace 't' with 'launcher' or 'field', https://github.com/phetsims/projectile-data-lab/issues/220
---
Index: js/common-sm/model/SMField.ts
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common-sm/model/SMField.ts b/js/common-sm/model/SMField.ts
--- a/js/common-sm/model/SMField.ts	(revision f269a55ec25131b4c17760a63c054b5720980104)
+++ b/js/common-sm/model/SMField.ts	(date 1709508695471)
@@ -14,26 +14,29 @@
 import projectileDataLab from '../../projectileDataLab.js';
 import { VSMFieldIdentifier } from '../../common-vsm/model/VSMFieldIdentifier.js';
 import { EmptySelfOptions } from '../../../../phet-core/js/optionize.js';
+import { TReadOnlyProperty } from '../../../../axon/js/imports.js';
 
 type SelfOptions = EmptySelfOptions;
 export type SMFieldOptions = SelfOptions & VSMFieldOptions;
 
 export default class SMField extends VSMField {
 
-  public readonly customLauncherMechanismProperty: DynamicProperty<LauncherMechanism, LauncherMechanism, Launcher>;
+  public readonly customLauncherMechanismProperty: TReadOnlyProperty<LauncherMechanism>;
+  private readonly _customLauncherMechanismProperty: DynamicProperty<LauncherMechanism, LauncherMechanism, Launcher>;
 
   public constructor( launchers: readonly Launcher[], identifier: VSMFieldIdentifier, providedOptions: SMFieldOptions ) {
     super( launchers, identifier, providedOptions );
 
-    this.customLauncherMechanismProperty = new DynamicProperty<LauncherMechanism, LauncherMechanism, Launcher>( this.launcherProperty, {
+    this._customLauncherMechanismProperty = new DynamicProperty<LauncherMechanism, LauncherMechanism, Launcher>( this.launcherProperty, {
       bidirectional: true,
       derive: launcher => launcher.launcherMechanismProperty
     } );
+    this.customLauncherMechanismProperty = this._customLauncherMechanismProperty;
   }
 
   public override reset(): void {
     super.reset();
-    this.customLauncherMechanismProperty.reset();
+    this._customLauncherMechanismProperty.reset();
   }
 }
 

[samreid]

@matthew-blackman and I aren't too excited about using double declarations to solve the access issues. We made one change above and @samreid will review the other occurrences to see how to proceed.

[samreid]

OK we addressed the remainder of the cases. We left a few DynamicProperty type declarations where there wasn't a bundle of other related dynamic properties or where the API was mostly necessary/valuable.

Closing.