[FIG(quote)[
[FIGCAPTION[
[1] [CITE@en[Safari 9.0]]
([TIME[2015-11-04 23:30:48 +09:00]] 版)
<https://developer.apple.com/library/safari/releasenotes/General/WhatsNewInSafari/Articles/Safari_9.html#//apple_ref/doc/uid/TP40014305-CH9-SW27>
]FIGCAPTION]

> The following ECMAScript 6 content is now supported by Safari:
> Weak Set

]FIG]


[2] ([TIME[2017-12-12 20:45:20 +09:00]])
<about:blank>

[3] [CITE@en-US[WeakSet - JavaScript | MDN]]
([TIME[2017-12-07 20:18:32 +09:00]])
<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet>