which-collection

Which kind of Collection (Map, Set, WeakMap, WeakSet) is this JavaScript value? Works cross-realm, without `instanceof`, and despite Symbol.toStringTag.

is-weakmap

Is this value a JS WeakMap? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

is-weakset

Is this value a JS WeakSet? This module works cross-realm/iframe, and despite ES6 @@toStringTag.