Function unionBy

Alias

unionBy<T, U>(arr1, arr2, mapper): T[]
Creates an array of unique values, in order, from all given arrays using a provided mapping function to determine equality.
Type Parameters
- T
  The type of elements in the array.
- U
  The type of mapped elements.
Parameters
- arr1: readonly T[]
  The first array.
- arr2: readonly T[]
  The second array.
- mapper: ((item: T) => U)
  The function to map array elements to comparison values.
  - - (item): U
    - Parameters
      item: T
      Returns U
Returns T[]
A new array containing the union of unique elements from arr1 and arr2, based on the values returned by the mapping function.
Example
```
// Custom mapping function for numbers (modulo comparison)
const moduloMapper = (x) => x % 3;
unionBy([1, 2, 3], [4, 5, 6], moduloMapper);
// Returns [1, 2, 3]
```
Example
```
// Custom mapping function for objects with an 'id' property
const idMapper = (obj) => obj.id;
unionBy([{ id: 1 }, { id: 2 }], [{ id: 2 }, { id: 3 }], idMapper);
// Returns [{ id: 1 }, { id: 2 }, { id: 3 }]
```
- Defined in src/array.ts:192