prepend() function

返回在前面添加给定元素,后面跟随 iterable 内容的 Iterable/AsyncIterable。

Signature:

declare function prepend<A>(a: A, iterable: Iterable<A>): IterableIterator<A>;

Example

const iter = prepend(4, [1, 2, 3]);
iter.next(); // {done:false, value: 4}
iter.next(); // {done:false, value: 1}
iter.next(); // {done:false, value: 2}
iter.next(); // {done:false, value: 3}

// with pipe
pipe([1, 2, 3], prepend(4), toArray); // [4, 1, 2, 3]

await pipe(Promise.resolve([1, 2, 3]), prepend(4), toArray); // [4, 1, 2, 3]

// with toAsync
await pipe(
  [Promise.resolve(1), Promise.resolve(2), Promise.resolve(3)],
  toAsync,
  prepend(4),
  toArray,
); // [4, 1, 2, 3]

Try It

see pipe, toAsync, toArray

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