Type definitions for 'Symbols as WeakMap keys' (#76)

src/compiler/commandLineParser.ts

@@ -212,7 +212,9 @@ const libEntries: [string, string][] = [
     ["es2022.string", "lib.es2022.string.d.ts"],
     ["es2022.regexp", "lib.es2022.regexp.d.ts"],
     ["es2023.array", "lib.es2023.array.d.ts"],
+    ["es2023.collection", "lib.es2023.collection.d.ts"],
     ["esnext.array", "lib.es2023.array.d.ts"],
+    ["esnext.collection", "lib.es2023.collection.d.ts"],
     ["esnext.symbol", "lib.es2019.symbol.d.ts"],
     ["esnext.asynciterable", "lib.es2018.asynciterable.d.ts"],
     ["esnext.intl", "lib.esnext.intl.d.ts"],

src/harness/fourslashInterfaceImpl.ts

@@ -1225,6 +1225,8 @@ export namespace Completion {
         varEntry("Float64Array"),
         interfaceEntry("Float64ArrayConstructor"),
         moduleEntry("Intl"),
+        typeEntry("WeakKey"),
+        interfaceEntry("WeakKeyTypes"),
     ];
 
     export const globalThisEntry: ExpectedCompletionEntry = {

src/lib/es2015.collection.d.ts

@@ -42,7 +42,7 @@ interface ReadonlyMap<K, V> {
     readonly size: number;
 }
 
-interface WeakMap<K extends object, V> {
+interface WeakMap<K extends WeakKey, V> {
     /**
      * Removes the specified element from the WeakMap.
      * @returns true if the element was successfully removed, or false if it was not present.
@@ -58,14 +58,14 @@ interface WeakMap<K extends object, V> {
     has(key: K): boolean;
     /**
      * Adds a new element with a specified key and value.
-     * @param key Must be an object.
+     * @param key Must be an object or symbol.
      */
     set(key: K, value: V): this;
 }
 
 interface WeakMapConstructor {
-    new <K extends object = object, V = any>(entries?: readonly (readonly [K, V])[] | null): WeakMap<K, V>;
-    readonly prototype: WeakMap<object, any>;
+    new <K extends WeakKey = WeakKey, V = any>(entries?: readonly [K, V][] | null): WeakMap<K, V>;
+    readonly prototype: WeakMap<WeakKey, any>;
 }
 declare var WeakMap: WeakMapConstructor;
 
@@ -107,9 +107,9 @@ interface ReadonlySet<T> {
     readonly size: number;
 }
 
-interface WeakSet<T extends object> {
+interface WeakSet<T extends WeakKey> {
     /**
-     * Appends a new object to the end of the WeakSet.
+     * Appends a new value to the end of the WeakSet.
      */
     add(value: T): this;
     /**
@@ -118,13 +118,13 @@ interface WeakSet<T extends object> {
      */
     delete(value: T): boolean;
     /**
-     * @returns a boolean indicating whether an object exists in the WeakSet or not.
+     * @returns a boolean indicating whether a value exists in the WeakSet or not.
      */
     has(value: T): boolean;
 }
 
 interface WeakSetConstructor {
-    new <T extends object = object>(values?: readonly T[] | null): WeakSet<T>;
-    readonly prototype: WeakSet<object>;
+    new <T extends WeakKey = WeakKey>(values?: readonly T[] | null): WeakSet<T>;
+    readonly prototype: WeakSet<WeakKey>;
 }
 declare var WeakSet: WeakSetConstructor;

src/lib/es2015.iterable.d.ts

@@ -141,10 +141,10 @@ interface MapConstructor {
     new <K, V>(iterable?: Iterable<readonly [K, V]> | null): Map<K, V>;
 }
 
-interface WeakMap<K extends object, V> { }
+interface WeakMap<K extends WeakKey, V> { }
 
 interface WeakMapConstructor {
-    new <K extends object, V>(iterable: Iterable<readonly [K, V]>): WeakMap<K, V>;
+    new <K extends WeakKey, V>(iterable: Iterable<readonly [K, V]>): WeakMap<K, V>;
 }
 
 interface Set<T> {
@@ -189,10 +189,10 @@ interface SetConstructor {
     new <T>(iterable?: Iterable<T> | null): Set<T>;
 }
 
-interface WeakSet<T extends object> { }
+interface WeakSet<T extends WeakKey> { }
 
 interface WeakSetConstructor {
-    new <T extends object = object>(iterable: Iterable<T>): WeakSet<T>;
+    new <T extends WeakKey = WeakKey>(iterable: Iterable<T>): WeakSet<T>;
 }
 
 interface Promise<T> { }

src/lib/es2015.symbol.wellknown.d.ts

@@ -119,15 +119,15 @@ interface Map<K, V> {
     readonly [Symbol.toStringTag]: string;
 }
 
-interface WeakMap<K extends object, V> {
+interface WeakMap<K extends WeakKey, V> {
     readonly [Symbol.toStringTag]: string;
 }
 
 interface Set<T> {
     readonly [Symbol.toStringTag]: string;
 }
 
-interface WeakSet<T extends object> {
+interface WeakSet<T extends WeakKey> {
     readonly [Symbol.toStringTag]: string;
 }
 

src/lib/es2021.weakref.d.ts

@@ -1,9 +1,10 @@
-interface WeakRef<T extends object> {
+interface WeakRef<T extends WeakKey> {
     readonly [Symbol.toStringTag]: "WeakRef";
 
     /**
-     * Returns the WeakRef instance's target object, or undefined if the target object has been
+     * Returns the WeakRef instance's target value, or undefined if the target value has been
      * reclaimed.
+     * In es2023 the value can be either a symbol or an object, in previous versions only object is permissible.
      */
     deref(): T | undefined;
 }
@@ -12,10 +13,11 @@ interface WeakRefConstructor {
     readonly prototype: WeakRef<any>;
 
     /**
-     * Creates a WeakRef instance for the given target object.
-     * @param target The target object for the WeakRef instance.
+     * Creates a WeakRef instance for the given target value.
+     * In es2023 the value can be either a symbol or an object, in previous versions only object is permissible.
+     * @param target The target value for the WeakRef instance.
      */
-    new<T extends object>(target: T): WeakRef<T>;
+    new<T extends WeakKey>(target: T): WeakRef<T>;
 }
 
 declare var WeakRef: WeakRefConstructor;
@@ -24,30 +26,31 @@ interface FinalizationRegistry<T> {
     readonly [Symbol.toStringTag]: "FinalizationRegistry";
 
     /**
-     * Registers an object with the registry.
-     * @param target The target object to register.
-     * @param heldValue The value to pass to the finalizer for this object. This cannot be the
-     * target object.
+     * Registers a value with the registry.
+     * In es2023 the value can be either a symbol or an object, in previous versions only object is permissible.
+     * @param target The target value to register.
+     * @param heldValue The value to pass to the finalizer for this value. This cannot be the
+     * target value.
      * @param unregisterToken The token to pass to the unregister method to unregister the target
-     * object. If provided (and not undefined), this must be an object. If not provided, the target
-     * cannot be unregistered.
+     * value. If not provided, the target cannot be unregistered.
      */
-    register(target: object, heldValue: T, unregisterToken?: object): void;
+    register(target: WeakKey, heldValue: T, unregisterToken?: WeakKey): void;
 
     /**
-     * Unregisters an object from the registry.
+     * Unregisters a value from the registry.
+     * In es2023 the value can be either a symbol or an object, in previous versions only object is permissible.
      * @param unregisterToken The token that was used as the unregisterToken argument when calling
-     * register to register the target object.
+     * register to register the target value.
      */
-    unregister(unregisterToken: object): void;
+    unregister(unregisterToken: WeakKey): void;
 }
 
 interface FinalizationRegistryConstructor {
     readonly prototype: FinalizationRegistry<any>;
 
     /**
      * Creates a finalization registry with an associated cleanup callback
-     * @param cleanupCallback The callback to call after an object in the registry has been reclaimed.
+     * @param cleanupCallback The callback to call after a value in the registry has been reclaimed.
      */
     new<T>(cleanupCallback: (heldValue: T) => void): FinalizationRegistry<T>;
 }

src/lib/es2023.collection.d.ts

@@ -0,0 +1,3 @@
+interface WeakKeyTypes {
+    symbol: symbol;
+}

src/lib/es2023.d.ts

@@ -1,2 +1,3 @@
 /// <reference lib="es2022" />
 /// <reference lib="es2023.array" />
+/// <reference lib="es2023.collection" />

src/lib/es5.d.ts

@@ -1647,6 +1647,15 @@ type Uncapitalize<S extends string> = intrinsic;
  */
 interface ThisType<T> { }
 
+/**
+ * Stores types to be used with WeakSet, WeakMap, WeakRef, and FinalizationRegistry
+ */
+interface WeakKeyTypes {
+    object: object;
+}
+
+type WeakKey = WeakKeyTypes[keyof WeakKeyTypes];
+
 /**
  * Represents a raw buffer of binary data, which is used to store data for the
  * different typed arrays. ArrayBuffers cannot be read from or written to directly,

src/lib/libs.json

@@ -66,6 +66,7 @@
         "es2022.string",
         "es2022.regexp",
         "es2023.array",
+        "es2023.collection",
         "esnext.intl",
         "decorators",
         "decorators.legacy",

tests/baselines/reference/acceptSymbolAsWeakType.js

@@ -0,0 +1,40 @@
+//// [tests/cases/compiler/acceptSymbolAsWeakType.ts] ////
+
+//// [acceptSymbolAsWeakType.ts]
+const s: symbol = Symbol('s');
+
+const ws = new WeakSet([s]);
+ws.add(s);
+ws.has(s);
+ws.delete(s);
+
+const wm = new WeakMap([[s, false]]);
+wm.set(s, true);
+wm.has(s);
+wm.get(s);
+wm.delete(s);
+
+const wr = new WeakRef(s);
+wr.deref();
+
+const f = new FinalizationRegistry(() => {});
+f.register(s, null);
+f.unregister(s);
+
+//// [acceptSymbolAsWeakType.js]
+"use strict";
+const s = Symbol('s');
+const ws = new WeakSet([s]);
+ws.add(s);
+ws.has(s);
+ws.delete(s);
+const wm = new WeakMap([[s, false]]);
+wm.set(s, true);
+wm.has(s);
+wm.get(s);
+wm.delete(s);
+const wr = new WeakRef(s);
+wr.deref();
+const f = new FinalizationRegistry(() => { });
+f.register(s, null);
+f.unregister(s);

tests/baselines/reference/acceptSymbolAsWeakType.symbols

@@ -0,0 +1,85 @@
+//// [tests/cases/compiler/acceptSymbolAsWeakType.ts] ////
+
+=== acceptSymbolAsWeakType.ts ===
+const s: symbol = Symbol('s');
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
+
+const ws = new WeakSet([s]);
+>ws : Symbol(ws, Decl(acceptSymbolAsWeakType.ts, 2, 5))
+>WeakSet : Symbol(WeakSet, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+ws.add(s);
+>ws.add : Symbol(WeakSet.add, Decl(lib.es2015.collection.d.ts, --, --))
+>ws : Symbol(ws, Decl(acceptSymbolAsWeakType.ts, 2, 5))
+>add : Symbol(WeakSet.add, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+ws.has(s);
+>ws.has : Symbol(WeakSet.has, Decl(lib.es2015.collection.d.ts, --, --))
+>ws : Symbol(ws, Decl(acceptSymbolAsWeakType.ts, 2, 5))
+>has : Symbol(WeakSet.has, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+ws.delete(s);
+>ws.delete : Symbol(WeakSet.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>ws : Symbol(ws, Decl(acceptSymbolAsWeakType.ts, 2, 5))
+>delete : Symbol(WeakSet.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+const wm = new WeakMap([[s, false]]);
+>wm : Symbol(wm, Decl(acceptSymbolAsWeakType.ts, 7, 5))
+>WeakMap : Symbol(WeakMap, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+wm.set(s, true);
+>wm.set : Symbol(WeakMap.set, Decl(lib.es2015.collection.d.ts, --, --))
+>wm : Symbol(wm, Decl(acceptSymbolAsWeakType.ts, 7, 5))
+>set : Symbol(WeakMap.set, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+wm.has(s);
+>wm.has : Symbol(WeakMap.has, Decl(lib.es2015.collection.d.ts, --, --))
+>wm : Symbol(wm, Decl(acceptSymbolAsWeakType.ts, 7, 5))
+>has : Symbol(WeakMap.has, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+wm.get(s);
+>wm.get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>wm : Symbol(wm, Decl(acceptSymbolAsWeakType.ts, 7, 5))
+>get : Symbol(WeakMap.get, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+wm.delete(s);
+>wm.delete : Symbol(WeakMap.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>wm : Symbol(wm, Decl(acceptSymbolAsWeakType.ts, 7, 5))
+>delete : Symbol(WeakMap.delete, Decl(lib.es2015.collection.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+const wr = new WeakRef(s);
+>wr : Symbol(wr, Decl(acceptSymbolAsWeakType.ts, 13, 5))
+>WeakRef : Symbol(WeakRef, Decl(lib.es2021.weakref.d.ts, --, --), Decl(lib.es2021.weakref.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+wr.deref();
+>wr.deref : Symbol(WeakRef.deref, Decl(lib.es2021.weakref.d.ts, --, --))
+>wr : Symbol(wr, Decl(acceptSymbolAsWeakType.ts, 13, 5))
+>deref : Symbol(WeakRef.deref, Decl(lib.es2021.weakref.d.ts, --, --))
+
+const f = new FinalizationRegistry(() => {});
+>f : Symbol(f, Decl(acceptSymbolAsWeakType.ts, 16, 5))
+>FinalizationRegistry : Symbol(FinalizationRegistry, Decl(lib.es2021.weakref.d.ts, --, --), Decl(lib.es2021.weakref.d.ts, --, --))
+
+f.register(s, null);
+>f.register : Symbol(FinalizationRegistry.register, Decl(lib.es2021.weakref.d.ts, --, --))
+>f : Symbol(f, Decl(acceptSymbolAsWeakType.ts, 16, 5))
+>register : Symbol(FinalizationRegistry.register, Decl(lib.es2021.weakref.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+
+f.unregister(s);
+>f.unregister : Symbol(FinalizationRegistry.unregister, Decl(lib.es2021.weakref.d.ts, --, --))
+>f : Symbol(f, Decl(acceptSymbolAsWeakType.ts, 16, 5))
+>unregister : Symbol(FinalizationRegistry.unregister, Decl(lib.es2021.weakref.d.ts, --, --))
+>s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
+