Fix(49525): Adds documentation for the Proxy type. (#49674)

* Adds documentation for the Proxy type.

* Removed trailing whitespace.

* Addresses PR feedback.

* Removes trivial comments and adds descriptive names.

src/lib/es2015.proxy.d.ts

@@ -1,21 +1,110 @@
 interface ProxyHandler<T extends object> {
+    /**
+     * A trap method for a function call.
+     * @param target The original callable object which is being proxied.
+     */
     apply?(target: T, thisArg: any, argArray: any[]): any;
+
+    /**
+     * A trap for the `new` operator.
+     * @param target The original object which is being proxied.
+     * @param newTarget The constructor that was originally called.
+     */
     construct?(target: T, argArray: any[], newTarget: Function): object;
-    defineProperty?(target: T, p: string | symbol, attributes: PropertyDescriptor): boolean;
+
+    /**
+     * A trap for `Object.defineProperty()`.
+     * @param target The original object which is being proxied.
+     * @returns A `Boolean` indicating whether or not the property has been defined.
+     */
+    defineProperty?(target: T, property: string | symbol, attributes: PropertyDescriptor): boolean;
+
+    /**
+     * A trap for the `delete` operator.
+     * @param target The original object which is being proxied.
+     * @param p The name or `Symbol` of the property to delete.
+     * @returns A `Boolean` indicating whether or not the property was deleted.
+     */
     deleteProperty?(target: T, p: string | symbol): boolean;
+
+    /**
+     * A trap for getting a property value.
+     * @param target The original object which is being proxied.
+     * @param p The name or `Symbol` of the property to get.
+     * @param receiver The proxy or an object that inherits from the proxy.
+     */
     get?(target: T, p: string | symbol, receiver: any): any;
+
+    /**
+     * A trap for `Object.getOwnPropertyDescriptor()`.
+     * @param target The original object which is being proxied.
+     * @param p The name of the property whose description should be retrieved.
+     */
     getOwnPropertyDescriptor?(target: T, p: string | symbol): PropertyDescriptor | undefined;
+
+    /**
+     * A trap for the `[[GetPrototypeOf]]` internal method.
+     * @param target The original object which is being proxied.
+     */
     getPrototypeOf?(target: T): object | null;
+
+    /**
+     * A trap for the `in` operator.
+     * @param target The original object which is being proxied.
+     * @param p The name or `Symbol` of the property to check for existence.
+     */
     has?(target: T, p: string | symbol): boolean;
+
+    /**
+     * A trap for `Object.isExtensible()`.
+     * @param target The original object which is being proxied.
+     */
     isExtensible?(target: T): boolean;
+
+    /**
+     * A trap for `Reflect.ownKeys()`.
+     * @param target The original object which is being proxied.
+     */
     ownKeys?(target: T): ArrayLike<string | symbol>;
+
+    /**
+     * A trap for `Object.preventExtensions()`.
+     * @param target The original object which is being proxied.
+     */
     preventExtensions?(target: T): boolean;
-    set?(target: T, p: string | symbol, value: any, receiver: any): boolean;
+
+    /**
+     * A trap for setting a property value.
+     * @param target The original object which is being proxied.
+     * @param p The name or `Symbol` of the property to set.
+     * @param receiver The object to which the assignment was originally directed.
+     * @returns `A `Boolean` indicating whether or not the property was set.
+     */
+    set?(target: T, p: string | symbol, newValue: any, receiver: any): boolean;
+
+    /**
+     * A trap for `Object.setPrototypeOf()`.
+     * @param target The original object which is being proxied.
+     * @param newPrototype The object's new prototype or `null`.
+     */
     setPrototypeOf?(target: T, v: object | null): boolean;
 }
 
 interface ProxyConstructor {
+    /**
+     * Creates a revocable Proxy object.
+     * @param target A target object to wrap with Proxy.
+     * @param handler An object whose properties define the behavior of Proxy when an operation is attempted on it.
+     */
     revocable<T extends object>(target: T, handler: ProxyHandler<T>): { proxy: T; revoke: () => void; };
+
+    /**
+     * Creates a Proxy object. The Proxy object allows you to create an object that can be used in place of the
+     * original object, but which may redefine fundamental Object operations like getting, setting, and defining
+     * properties. Proxy objects are commonly used to log property accesses, validate, format, or sanitize inputs.
+     * @param target A target object to wrap with Proxy.
+     * @param handler An object whose properties define the behavior of Proxy when an operation is attempted on it.
+     */
     new <T extends object>(target: T, handler: ProxyHandler<T>): T;
 }
 declare var Proxy: ProxyConstructor;