Last active
October 7, 2023 23:19
-
-
Save jorendorff/85d74ef7dce0118664535f84d57d6788 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function wetA() {}; | |
function wetB() {}; | |
wetB.prototype = new wetA(); | |
var wet_b = new wetB(); | |
// Reflect.get(wetB, "prototype") === Reflect.getPrototypeOf(wet_b); | |
// boilerplate, not really that important | |
function valueType(value) { | |
if (value === null) | |
return "primitive"; | |
const type = typeof value; | |
if ((type != "function") && (type != "object")) | |
return "primitive"; | |
return type; | |
} | |
// The WeakMap for the "dry" object graph's proxies | |
const wetToDry = new WeakMap(); | |
// Map from shadow targets to real targets. | |
const shadowToWet = new WeakMap(); | |
function wrap(wet) { | |
if (valueType(wet) === "primitive") | |
return wet; | |
let dry = wetToDry.get(wet); | |
if (dry === undefined) { | |
let shadow = {}; | |
dry = new Proxy(shadow, h); | |
wetToDry.set(wet, dry); | |
shadowToWet.set(shadow, wet); | |
} | |
return dry; | |
} | |
// The handler for the "dry" object graph's proxies | |
const h = { | |
get: function(target, key, receiver) { | |
let realTarget = shadowToWet.get(target); | |
return wrap(Reflect.get(realTarget, key, receiver)); | |
}, | |
getPrototypeOf: function(target) { | |
let realTarget = shadowToWet.get(target); | |
let rv = wrap(Reflect.getPrototypeOf(realTarget)); | |
Reflect.setPrototypeOf(target, rv); | |
return rv; | |
} | |
}; | |
var dry_b = wrap(wet_b); | |
var dryB = wrap(wetB); | |
// Everything is wonderful! | |
Object.freeze(wet_b); | |
//Object.freeze(wetB); | |
const assert = require('assert'); | |
var proto1 = Reflect.getPrototypeOf(wet_b); | |
var proto2 = Reflect.get(wetB, "prototype"); | |
assert(proto1 === proto2); | |
var proto1 = Reflect.getPrototypeOf(dry_b); | |
var proto2 = Reflect.get(dryB, "prototype"); | |
assert(proto1 === proto2); |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment