All files filter.ts

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100% Branches 0/0
100% Functions 2/2
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import { Collection, asIterable } from './utils'
import Sequence from './Sequence'
 
/**
 * Return a Sequence that contains the elements from the input collection that satisfy the predicate.
 * @param collection A collection to filter.
 * @param predicate A function that tests if a value satisfies some condition.
 */
function filter<T>(collection: Collection<T>, predicate: (value: T, index: number) => boolean) {
 
  const iterable = asIterable(collection)
  return new Sequence(function* () {
    let index = 0
    for(const value of iterable) {
      if(predicate(value, index++)) {
        yield value
      }
    }
  })
}
 
export default filter