All files flatMap.ts

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
5x
5x
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5x
 
import { Collection, asIterable } from './utils'
import Sequence from './Sequence'
 
function flatMap<T, U>(collection: Collection<T>, fn: (value: T, index: number) => Collection<U>) {
  const iterable = asIterable(collection)
  return new Sequence(function* () {
    let index = 0
    for(const value of iterable) {
      const result = asIterable(fn(value, index++))
      for(const innerValue of result) {
        yield innerValue
      }
    }
  })
}
 
export default flatMap