Add WeakRef type

types/WeakRef.d.ts

@@ -0,0 +1,31 @@
+/// <reference no-default-lib="true"/>
+/// <reference types="@rbxts/types"/>
+
+/**
+ * A WeakRef object is a reference to an object that does not prevent the object from being garbage collected.
+ * Note that references to Roblox instances are never weak.
+ */
+interface WeakRef<T extends object> {
+	/**
+	 * **DO NOT USE!**
+	 *
+	 * This field exists to force TypeScript to recognize this as a nominal type
+	 * @hidden
+	 * @deprecated
+	 */
+	readonly _nominal_WeakRef: unique symbol;
+
+	/**
+	 * Returns the WeakRef instance's target value, or undefined if the target value has been reclaimed.
+	 */
+	deref(): T | undefined;
+}
+
+interface WeakRefConstructor {
+	/**
+	 * Creates a WeakRef instance for the given target value.
+	 * @param target The target value for the WeakRef instance.
+	 */
+	new <T extends object>(target: T): WeakRef<T>;
+}
+declare const WeakRef: WeakRefConstructor;