惰性遍历数组

[CarterLi]

function* range(start: number, end: number) {
  for (let i = start; i <= end; ++i) yield i;
}
function* map(iter: IterableIterator<number>, fn: (n: number) => number) {
  for (const x of iter) yield fn(x);
}
function* reverse(iter: IterableIterator<number>): IterableIterator<number> {
  for (const x of iter) yield* reverse(iter), yield x;
}
function foreach(iter: IterableIterator<number>, fn: (n: number) => void) {
  for (const x of iter) fn(x);
}

var numbers = range(1, 10);
numbers = map(numbers, function (n) { return n * n });
numbers = reverse(numbers);
foreach(numbers, console.log);

[CarterLi]

[手动斜眼]