find the union of two maps in javascript

One way to find the union of two maps in JavaScript is by using the spread operator and the keys() method.

Here's an example code snippet:

index.tsx
const map1 = new Map([
  ['a', 1],
  ['b', 2],
  ['c', 3]
]);

const map2 = new Map([
  ['d', 4],
  ['e', 5],
  ['f', 6]
]);

const union = new Map([...map1, ...map2]);

console.log(union);
// Output: Map(6) {"a" => 1, "b" => 2, "c" => 3, "d" => 4, "e" => 5, "f" => 6}
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In this example, we have two maps map1 and map2. To find their union, we create a new map union and use the spread operator to combine the key-value pairs of map1 and map2.

The keys() method is not used explicitly in this example, but it is used indirectly by the spread operator, which converts the map objects into arrays of key-value pairs using the entries() method.