tap(callback)

• callback <Function> (chunks) => void 在每个批次调用一次。
• 返回：<Function> 无状态变换。

创建一个能够观察批处理而不修改它们的通道转换。适用于日志记录、指标或调试。

🌐 Create a pass-through transform that observes batches without modifying them. Useful for logging, metrics, or debugging.

import { from, pull, text, tap } from 'node:stream/iter';

const result = pull(
  from('hello'),
  tap((chunks) => console.log('Batch size:', chunks.length)),
);
console.log(await text(result));const { from, pull, text, tap } = require('node:stream/iter');

async function run() {
  const result = pull(
    from('hello'),
    tap((chunks) => console.log('Batch size:', chunks.length)),
  );
  console.log(await text(result));
}

run().catch(console.error);拷贝

tap() 故意不阻止 tapping 回调对块的就地修改；但返回值会被忽略。