[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" |
分类:
Javascript
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