Support for New ECMAScript Set Methods

TL;DR

ECMAScriptに追加された新しいSetのメソッド群が定義された。

GitHub - tc39/proposal-set-methods: Proposal for new Set methods in JSGitHub

const a1 = [];
const a2 = [];

a1.union(a2);
a1.difference(a2);

intersection,union,difference

https://stackblitz.com/edit/stackblitz-starters-m2gdh8?file=index.html

isDisjointFrom,isSubsetOf,isSupersetOf

https://stackblitz.com/edit/stackblitz-starters-dx1wgx?file=index.html