Constructs a new ReactiveMap with the given initial content.
Optional
// Emptyconst set1 = reactiveSet<string>();// With initial contentconst set2 = reactiveSet<string>(["foo", "bar"]); Copy
// Emptyconst set1 = reactiveSet<string>();// With initial contentconst set2 = reactiveSet<string>(["foo", "bar"]);
Constructs a new ReactiveMap with the given initial content.