es6-proxy

问题 I'm hoping to proxy the canvas API so I can test that abstracted methods do actually draw to the canvas, however I'm hitting issues where after proxing I get an error: 'strokeStyle' setter called on an object that does not implement interface CanvasRenderingContext2D This code is simplified but throws the same error: /** !NB: This snippet will probably only run in Firefox */ var canvas = document.createElement("canvas"); canvas.width = 100; canvas.height = 100; canvas.style.backgroundColor =

问题 First of all, I want to clarify, I know that with is deprecated , and using it is generally a bad practice . However, my question is about a special case: using a special Proxy object as the parameter of with. Background I'm working on a project, where I have to limit access of a piece of code to the global scope. One approach might be to use a loop with eval , that creates constant variables with the value of undefined for each property of the global object, but that seems even worse than

问题 First of all, I want to clarify, I know that with is deprecated , and using it is generally a bad practice . However, my question is about a special case: using a special Proxy object as the parameter of with. Background I'm working on a project, where I have to limit access of a piece of code to the global scope. One approach might be to use a loop with eval , that creates constant variables with the value of undefined for each property of the global object, but that seems even worse than

问题 First of all, I want to clarify, I know that with is deprecated , and using it is generally a bad practice . However, my question is about a special case: using a special Proxy object as the parameter of with. Background I'm working on a project, where I have to limit access of a piece of code to the global scope. One approach might be to use a loop with eval , that creates constant variables with the value of undefined for each property of the global object, but that seems even worse than

问题 I am trying to make a Proxy object of Image to trap properties but even with an empty handler I get an error message. TypeError: Argument 1 of Node.appendChild does not implement interface Node. The proxy object is suppose to act as the target object so this baffles me a little. As far as I understand you should be able to do this with DOM nodes as well (?). Also : I cannot start loading the image and have the onload handler triggered when setting the src property. How should I use the Proxy

问题 I was using proxy get method fine. Then I tried using it on a function and quickly realized I needed to use the apply method. This simple example is not working. It never enters apply. Node looks to support apply https://node.green/#ES2015-built-ins-Proxy--apply--handler. Not sure what I'm doing wrong. var Foo = { runme: function() { return 1; } }; var Magic = { Foo: Foo }; Magic.Foo = new Proxy(Object.assign({}, Magic.Foo), { apply: function(target, thisArg, argumentsList) { // never gets in

来源： https://stackoverflow.com/questions/59003675/how-to-detect-the-end-of-a-get-sequence-in-a-proxy-object

问题 I recently got to know about ES6 proxies but I don't see a good reason to use it. I mean, everything that one could do with Proxy can be done without it, except if I'm missing something. For example, most folks talk about validation when it comes to proxy but one could apply some JS goodness to validate and everyone is fine. I would appreciate if someone could open my eyes to some major use cases of Proxies. Thanks! 回答1: I mean, every thing that one could do with Proxy can be done without it.

问题 This is the code that's causing the error: console.log(objectWithProxyProperty); the error that I am dealing with is either, TypeError: Cannot read property 'apply' of undefined or Error: The assertion library used does not have a 'inspect' property or method. depending on which checks I use, which is demostrated in the code below. What's clear is that the 'inspect' property is being sent to the get method, but 'inspect' is not a Symbol AND 'inspect' cannot be read with prop in chaiAssert

问题 I have the following class that is utilizing a Proxy for getting properties and methods: class User extends Model { static table = 'users'; _attributes = { id: 1, firstName: 'Testing', lastName: 'Test' }; constructor() { return new Proxy(this, { get: function(target, name) { // proxy getting code for functions and properties } }); } client() { return this.hasOne(Client, 'clientID'); } } Within the get method of the proxy, retrieving attributes is trivial. I just check for their existence