How to allow duplicates with ImmutableJS

Question

I need an Immutable Set that allows duplicate values. That is unordered collection with duplicate values allowed.

Answer 1

What you want is usually called multiset or bag; however, immutable.js does not implement such a collection. Simple workaround is to use immutable Map, mapping individual elements (you would like to store in the set) to their quantities.

Example: multiset {a,a,a,b,b} may be represented as {a: 3, b: 2}