Takes two argument, self and other, and returns a boolean indicating if all the elements in other are also contained within self.
self
other
If Set.isSupersetOf() is not supported then a polyfill will be used.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/isSupersetOf
Takes two argument,
selfandother, and returns a boolean indicating if all the elements inotherare also contained withinself.If Set.isSupersetOf() is not supported then a polyfill will be used.