lib/index.esm.js
function get(key) {
    var entry = _collectionStrong.getEntry(_validateCollection(this, MAP), key);
    return entry && entry.v;
  }
function get(key) {
    var entry = _collectionStrong.getEntry(_validateCollection(this, MAP), key);
    return entry && entry.v;
  }
23.1.3.6 Map.prototype.get(key)