The following ECMAScript 6 content is now supported by Safari:
Symbol Objects
[2] Write structured clone algorithm in terms of ECMAScript · whatwg/html@bfb960c ( 版) <https://github.com/whatwg/html/commit/bfb960c938580c95e77365e614218b952f96375b>
[3] Add the symbol type (domenic著, ) <https://github.com/heycam/webidl/commit/d6c3ddbfe74d4a6192aae98bcf03b6c323582e8d>
[4] 27553 – Support Symbol () <https://www.w3.org/Bugs/Public/show_bug.cgi?id=27553>
[5] `any` type conversion does not take into account of symbols · Issue #301 · heycam/webidl () <https://github.com/heycam/webidl/issues/301>
[6] Add the symbol type by domenic · Pull Request #377 · heycam/webidl () <https://github.com/heycam/webidl/pull/377>
[7] Handle Symbols correctly in legacy platform object's [[DefineOwnPrope… (TimothyGu著, ) <https://github.com/heycam/webidl/commit/c062489e7289c1614f695599783af3f8dbe6ef9e>