how to use the unionby function from the lodash library in typescript

To use the unionBy function from the Lodash library in TypeScript, you can import it as follows:

index.ts
import { unionBy } from 'lodash';
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The unionBy function takes three arguments:

1. An array of objects or primitives to be unioned.
2. An array of objects or primitives to be unioned.
3. A function to extract a value for comparison from each element in both arrays.

Here's an example usage of unionBy function:

index.ts
interface Person {
  id: number;
  name: string;
}

const arr1: Person[] = [
  { id: 1, name: 'Alice' },
  { id: 2, name: 'Bob' },
  { id: 3, name: 'Charlie' },
];

const arr2: Person[] = [
  { id: 1, name: 'Alice' },
  { id: 4, name: 'David' },
];

const result = unionBy(arr1, arr2, 'id');
console.log(result); // [{ id: 1, name: 'Alice' }, { id: 2, name: 'Bob' }, { id: 3, name: 'Charlie' }, { id: 4, name: 'David' }]
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In this example, we're using unionBy to combine two arrays of Person objects based on their id fields. The resulting array contains unique elements from both arrays, with duplicates removed based on their id values.