Function ofSimple

ofSimple<V>(groupBy?: ToString<V>, valueEq?: IsEqual<V>): IMapOfImmutable<V>
A simple immutable map of arrays, without events. It can store multiple values under the same key.

For a fancier approaches, consider ofArrayMutable, ofCircularMutable or ofSetMutable.
Type Parameters
- V
  Type of items
Parameters
- groupBy: ToString<V> = defaultKeyer
- valueEq: IsEqual<V> = ...
Returns IMapOfImmutable<V>
New instance
Example
```
let m = mapSimple();
m = m.add(`hello`, 1, 2, 3); // Adds numbers under key `hello`
m = m.delete(`hello`);       // Deletes everything under `hello`

const hellos = m.get(`hello`); // Get list of items under `hello`
```