find the intersection of two maps in javascript

To find the intersection of two maps in JavaScript, we can first convert each map into an array of entries using the Map.entries() method. Then we can use the Array.filter() method to filter the entries of the first map based on whether the key exists in the second map. Finally, we can create a new map from the filtered entries using the Map() constructor.

Here's an example code snippet that demonstrates this approach:

index.tsx
const map1 = new Map([
  [1, 'a'],
  [2, 'b'],
  [3, 'c']
]);
const map2 = new Map([
  [2, 'x'],
  [3, 'y'],
  [4, 'z']
]);

const entries1 = Array.from(map1.entries());
const entries2 = Array.from(map2.entries());

const intersection = new Map(entries1.filter(
  ([key, value]) => map2.has(key)
));

console.log(intersection);
// Output: Map(2) { 2 => 'b', 3 => 'c' }
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In this example, map1 and map2 are two maps we want to find the intersection of. We convert these maps to arrays of entries using the Map.entries() method and store them in entries1 and entries2, respectively.

Then we create a new map called intersection by filtering out the entries of entries1 that don't have a key that exists in map2 using the Array.filter() method. Finally, we convert the filtered entries back to a map using the Map() constructor and store it in intersection.

The output of this code snippet is a map that contains the key-value pairs that exist in both map1 and map2.