Merging maps

Merging two or more maps together means that you want one map with key-value pairs from every map. The challenge comes where two of the maps have the same key.

Merging maps by key

When merging maps, there's always the chance that keys will conflict. The question is, which value gets used? Let's illustrate this idea by merging two simple lists together:

const myMap1 = Map.of(
  'one', 1, 'two', 2, 'three', 3
);
const myMap2 = Map.of(
  'two', 22, 'three', 33, 'four', 4
);
const myMergedMap = myMap1.merge(myMap2);

console.log('myMap1', myMap1.toJS());
// -> myMap1 { one: 1, two: 2, three: 3 }
console.log('myMap2', myMap2.toJS())...