[Javascript] Customize Behavior when Accessing Properties with Proxy Handlers

A Proxy allows you to trap what happens when you try to get a property value off of an object and do some behavior before the value is accessed. For example, you could check the name of the property and always return a certain value or even check if the property is undefined and return some default. The options are unlimited.

 

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

"use strict"   let person = {   name: "John" }   let handler = {   get(target, key) {     if (key === "name") {       return "Mindy"     }       if (Reflect.has(target, key)) {       return Reflect.get(target, key)     }       return "You tried to access something undefined"   } }   person = new Proxy(person, handler)   console.log(person.name) // "Mindy" console.log(person.age) // "You tried to access something undefined"