What is the Reflect API and when should you use it?

The Reflect API is a built-in object that provides methods for interceptable JavaScript operations. It mirrors many Object methods but with some improvements.

     const obj = { name: 'John', age: 30 };

     // Setting properties
     Reflect.set(obj, 'city', 'New York');

     // Getting properties
     console.log(Reflect.get(obj, 'name')); // 'John'

     // Checking property existence
     console.log(Reflect.has(obj, 'age')); // true

     // Deleting properties
     Reflect.deleteProperty(obj, 'age');
     

Advantages over Object methods:

1. Returns boolean for success/failure:

        // Object.defineProperty throws on failure
        try {
          Object.defineProperty(obj, 'prop', { value: 1 });
        } catch (e) {}

        // Reflect.defineProperty returns boolean
        const success = Reflect.defineProperty(obj, 'prop', { value: 1 });
        

1. Works perfectly with Proxy traps:

        const handler = {
          set(target, prop, value, receiver) {
            console.log(`Setting ${prop} to ${value}`);
            return Reflect.set(target, prop, value, receiver);
          }
        };

        const proxy = new Proxy({}, handler);
        proxy.name = 'John'; // Logs: Setting name to John
        

1. Function.prototype.apply made simpler:

        // Old way
        Function.prototype.apply.call(Math.max, null, [1, 2, 3]);

        // Reflect way
        Reflect.apply(Math.max, null, [1, 2, 3]); // 3