Method select

packs/standalone/src/tuple.ts:16–23

(selector: (x: T) => S)

  }

  select<S>(selector: (x: T) => S) {
    const [prev, next] = this.spread();
    const [newPrev, newNext] = [
      prev === null ? null : prev === undefined ? undefined : selector(prev),
      next === null ? null : next === undefined ? undefined : selector(next)
    ];
    return new Tuple(newPrev, newNext);
  }

  selectMany<S extends { key?: any }>(selector: (x: T) => S[]) {
    const [prev, next] = this.spread();