[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.

"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"

巴特西

[Javascript] Customize Behavior when Accessing Properties with Proxy Handlers

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