You could use it to avoid bugs involving circular references when iterating,
for example:
```js
function iterate(O, fn) {
if (O == null) return O;
let objects = new WeakSet();
iterate_inner(‘’, O, objects, fn);
return O;
function iterate_inner(name, O, objects, fn) {
for (let key of Reflect.ownKeys(O)) {
let value = O[key];
let niceName = name ? `${name}.${key}` : key;
if (typeof value === “object” && value) {
// Avoid recursing into circular reference
if (objects.has(value)) {
continue;
} else {
fn(value, niceName);
objects.add(value);
iterate_inner(niceName, value, objects, fn);
}
} else {
fn(value, niceName);
}
}
}
}
```
> On Jun 2, 2015, at 11:14 AM, Domenic Denicola <[email protected]> wrote:
>
> WeakSets are perfect for branding and are how I would expect web platform
> class branding to be explained.
>
> ```js
> const foos = new WeakSet();
>
> class Foo {
> constructor() {
> foos.add(this);
> }
>
> method() {
> if (!foos.has(this)) {
> throw new TypeError("Foo.prototype.method called on an incompatible
> object!");
> }
> }
> }
> ```
>
> _______________________________________________
> es-discuss mailing list
> [email protected]
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