What is the difference between a Proxy constructor and a Reflect?

Question

Is there a significant difference between Reflect and Proxy ?

From what is documented, it seems that they have almost the same capabilities, except:

• Reflect the ability to point only one trap at a time.
• Proxy server revocable .
• Proxy constructor.

If the above list summarizes all the differences, then what is the reason for both?

Answer 1

Reflect and Proxy have completely different goals and different capabilities.

MDN describes proxies as follows :

A Proxy object is used to define user behavior for basic operations (for example, searching for properties, assigning, listing, calling functions, etc.).

And reflect in this way :

Reflection is a built-in object that provides methods for intercepting JavaScript operations. The methods are the same as the proxy handler methods.

I understand that you probably already read this, so I will use the example to explain it further.

Let's say you have an object:

 const obj = { a: 'foo', b: 'bar', }; 

You can access property a with this property:

 console.log(obj.a); // 'foo' 

You can do the same with the Reflect.get() method:

 console.log(Reflect.get(obj, 'a')); // 'foo' 

You can also create proxies for this object using the Proxy constructor. We will use the get handler to intercept all property searches.

 const proxy = new Proxy(obj, { get(target, property) { return property in target ? target[property] : 'default'; }, }); 

Now, using either the accessor property or Reflect.get() to get the undefined property, we get the string 'default' :

 console.log(proxy.c); // 'default' console.log(Reflect.get(proxy, 'c')); // 'default' 

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Proxy and Reflect can work great together. For example, you can create a proxy with a no-op get handler using Reflect:

 new Proxy(obj, { get: Reflect.get, });