readable.some(fn[, options])

• fn <Function> | <AsyncFunction> 调用流的每个块的函数。

  ¥fn <Function> | <AsyncFunction> a function to call on each chunk of the stream.

  • data <any> 来自流的数据块。

    ¥data <any> a chunk of data from the stream.

  • options <Object>

    • signal <AbortSignal> 如果流被销毁则中止，允许提前中止 fn 调用。

      ¥signal <AbortSignal> aborted if the stream is destroyed allowing to abort the fn call early.

• options <Object>

  • concurrency <number> 一次调用流的 fn 的最大并发调用数。默认值：1。

    ¥concurrency <number> the maximum concurrent invocation of fn to call on the stream at once. Default: 1.

  • signal <AbortSignal> 如果信号中止，允许销毁流。

    ¥signal <AbortSignal> allows destroying the stream if the signal is aborted.

• 返回：如果 fn 至少为其中一个块返回真值，则 <Promise> 是评估 true 的 promise。

  ¥Returns: <Promise> a promise evaluating to true if fn returned a truthy value for at least one of the chunks.

此方法类似于 Array.prototype.some，并在流中的每个块上调用 fn，直到等待的返回值为 true（或任何真值）。一旦对块等待返回值的 fn 调用为真，流就会被销毁，并用 true 实现 promise。如果对块的 fn 调用都没有返回真值，则 promise 由 false 实现。

¥This method is similar to Array.prototype.some and calls fn on each chunk in the stream until the awaited return value is true (or any truthy value). Once an fn call on a chunk awaited return value is truthy, the stream is destroyed and the promise is fulfilled with true. If none of the fn calls on the chunks return a truthy value, the promise is fulfilled with false.

import { Readable } from 'node:stream';
import { stat } from 'node:fs/promises';

// With a synchronous predicate.
await Readable.from([1, 2, 3, 4]).some((x) => x > 2); // true
await Readable.from([1, 2, 3, 4]).some((x) => x < 0); // false

// With an asynchronous predicate, making at most 2 file checks at a time.
const anyBigFile = await Readable.from([
  'file1',
  'file2',
  'file3',
]).some(async (fileName) => {
  const stats = await stat(fileName);
  return stats.size > 1024 * 1024;
}, { concurrency: 2 });
console.log(anyBigFile); // `true` if any file in the list is bigger than 1MB
console.log('done'); // Stream has finished 拷贝