All Questions
18
questions
0
votes
1
answer
65
views
Detect direct instances in JavaScript
A couple of years ago, I wanted figure how to create a type check for class A that returns true only for objects instantiated by new A(). For this, I wrote the class like this:
class A {
static #...
- 2,704
0
votes
1
answer
64
views
A proxied JS child class assigns a wrong prototype to an instance
Some interesting case which I don't understand.
I proxy classes and extend a child class from a proxied base class.
When a child is constructed inside the construct trap for some reason a wrong ...
- 19.4k
1
vote
3
answers
75
views
How can I detect changes to arbitrary private members with an ES6 proxy in Javascript?
I am working on building a 2D renderer with the Javascript canvas API, and I am trying to improve performance by skipping renders when no changes to the state of any renderable objects have occurred.
...
- 15
2
votes
1
answer
767
views
Is there a away to Bind a Proxy object to the ES6 class constructor?
In ES5^ I can create a proxy object and bind it to the other functions constructors, see what I want to do in the example below:
function X() {
this.x = `${this.anyAttr} it's a trap`;
}
...
2
votes
2
answers
3k
views
How to make a getter proxy for all instances of a class in javascript?
Proxies can be used to define 'general getters' for objects. For example
var obj = {'a':3, 'b':4 };
var proxy = new Proxy( obj, {
get: function(obj, prop){return obj[prop]+10}
} );
proxy.a //13
...
1
vote
2
answers
1k
views
How to extend a class wrapped in a Proxy
I have a complex class that requires certain arguments to be passed to the constructor. However, I am exposing a simplified API to customers.
My internal class looks something like this:
class Foo {
...
- 25.9k
1
vote
1
answer
2k
views
how to override class methods using javascript proxy
this is my class
class Chrome {
constructor(browser, page) {
this.browser;
this.page;
}
async launch() {
if (!this.browser) {
console.log("launching browser...");
this....
- 3,258
1
vote
1
answer
508
views
Custom elements with proxied has, get & set
My goal is to create a class ObservableElement extending HTMLElement such that it can be used to define custom elements, e g:
customElements.define('an-observable-elem', class extends ...
- 85
0
votes
0
answers
1k
views
How to use Proxy to intercept every function of an object in JavaScript or E6?
I have a class A, defined like below.(All sample code is simplified for privacy)
class A{
Func1(){
}
Func2(){
}
Func3(){
}
}
And I want to make every function in A ...
- 427
4
votes
2
answers
2k
views
How to wrap object being constructed with Proxy inside constructor?
I understand that Proxy can be used to alter object-level behaviors, such as bracket notation get and set. All the examples I can find show constructing an object and then wrapping it with a Proxy ...
- 1,653
0
votes
1
answer
349
views
javascript create dynamic class by object
Task: I want to create a dynamic class by a given JSON Object in ES6.
After a lot of reading in the MDN web docs and much stackoverflow questions i'm totally confused how to get this work.
JSON ...
- 28
1
vote
1
answer
677
views
sessionStorage proxy class scope
I am wondering how to access the native sessionStorage scope from within my custom methods.
My example:
https://jsfiddle.net/3mc7ao7j/1/
At line 3 I would like to be able to proxy through to my ...
- 20k
17
votes
1
answer
3k
views
How to Proxy Custom Element (Web Component)
class A extends HTMLElement {
constructor() {
super()
return new Proxy(this, {})
}
}
window.customElements.define('a-element', A)
<a-element></a-element>
How can ...
- 260
0
votes
1
answer
339
views
Why can’t a proxy trap invoke Function.prototype.apply to construct an ES6 class?
I'm trying to Proxy a ES6 constructor (mostly trying to emulate Python's descriptors for fun and learning):
class _Record {
constructor(data) {
this._data = data;
}
}
const ...
- 4,617
2
votes
0
answers
357
views
Subclass ES6 Proxied Class
I want to Subclass a Proxied ES6 Class. It works just fine in Firefox and Chrome, but Safari 10 throws an error:
let SuperClass = class {
constructor() {
console.log('SuperClass ...
- 41