DO NOT MERGE THIS COMMIT - Revert "fix assignment of subtypes (#7) (#42)"

This reverts commit b8ee846.

Author: divdavem

src/computed.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {defaultEquals, ValueEqualityComparer} from './equality.js';
+import {defaultEquals, ValueEqualityFn} from './equality.js';
 import {
   consumerAfterComputation,
   consumerBeforeComputation,
@@ -22,7 +22,7 @@ import {
  *
  * `Computed`s are both producers and consumers of reactivity.
  */
-export interface ComputedNode<T> extends ReactiveNode, ValueEqualityComparer<T> {
+export interface ComputedNode<T> extends ReactiveNode {
   /**
    * Current value of the computation, or one of the sentinel values above (`UNSET`, `COMPUTING`,
    * `ERROR`).
@@ -39,6 +39,8 @@ export interface ComputedNode<T> extends ReactiveNode, ValueEqualityComparer<T>
    * The computation function which will produce a new value.
    */
   computation: () => T;
+
+  equal: ValueEqualityFn<T>;
 }
 
 export type ComputedGetter<T> = (() => T) & {

src/equality.ts

@@ -7,13 +7,9 @@
  */
 
 /**
- * An interface representing a comparison strategy to determine if two values are equal.
- *
- * @template T The type of the values to be compared.
+ * A comparison function which can determine if two values are equal.
  */
-export interface ValueEqualityComparer<T> {
-  equal(a: T, b: T): boolean;
-}
+export type ValueEqualityFn<T> = (a: T, b: T) => boolean;
 
 /**
  * The default equality function used for `signal` and `computed`, which uses referential equality.

src/public-api-types.ts

@@ -93,19 +93,3 @@ expectTypeOf<keyof Signal.subtle.Watcher & string>().toEqualTypeOf<
 expectTypeOf(new Signal.State(0)).toEqualTypeOf<Signal.State<number>>();
 expectTypeOf(new Signal.State(0).get()).toEqualTypeOf<number>();
 expectTypeOf(new Signal.State(0).set(1)).toEqualTypeOf<void>();
-
-/**
- * Assigning subtypes works
- */
-expectTypeOf<Signal.Computed<Narrower>>().toMatchTypeOf<Signal.Computed<Broader>>();
-expectTypeOf<Signal.State<Narrower>>().toMatchTypeOf<Signal.State<Broader>>();
-
-/**
- * Test data types
- */
-interface Broader {
-  strProp: string;
-}
-interface Narrower extends Broader {
-  numProp: number;
-}

src/signal.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {defaultEquals, ValueEqualityComparer} from './equality.js';
+import {defaultEquals, ValueEqualityFn} from './equality.js';
 import {throwInvalidWriteToSignalError} from './errors.js';
 import {
   producerAccessed,
@@ -30,8 +30,9 @@ declare const ngDevMode: boolean | undefined;
  */
 let postSignalSetFn: (() => void) | null = null;
 
-export interface SignalNode<T> extends ReactiveNode, ValueEqualityComparer<T> {
+export interface SignalNode<T> extends ReactiveNode {
   value: T;
+  equal: ValueEqualityFn<T>;
 }
 
 export type SignalBaseGetter<T> = (() => T) & {readonly [SIGNAL]: unknown};