Function map

map<T, O>(mapper): OperationFunction<T, O>
Returns a Stream that yields elements from the source transformed by the mapper.
Type Parameters
- T
  Type of items in the source.
- O
  Type of items in the result.
Parameters
- mapper: ((value: T, index: number) => O)
  Function to transform elements.
  - - (value, index): O
    - Parameters
      value: T
      index: number
      Returns O
Returns OperationFunction<T, O>
Operation that yields elements from the source transformed by the mapper.
Example
```
const result = map((x) => x * 2)([1, 2, 3]);
console.log([...result]); // [2, 4, 6]
```
- Defined in operations/map/map.ts:31