readable[Symbol.asyncIterator]()


const fs = require('node:fs');

async function print(readable) {
  readable.setEncoding('utf8');
  let data = '';
  for await (const chunk of readable) {
    data += chunk;
  }
  console.log(data);
}

print(fs.createReadStream('file')).catch(console.error); 

如果循环通过 breakreturnthrow 终止,流将会被销毁。换句话说,对流进行迭代将会完全消耗该流。流会以大小等于 highWaterMark 选项的块读取。在上面的代码示例中,如果文件数据少于 64 KiB,由于没有为 fs.createReadStream() 提供 highWaterMark 选项,数据将会在一个单独的块中读取。

【If the loop terminates with a break, return, or a throw, the stream will be destroyed. In other terms, iterating over a stream will consume the stream fully. The stream will be read in chunks of size equal to the highWaterMark option. In the code example above, data will be in a single chunk if the file has less then 64 KiB of data because no highWaterMark option is provided to fs.createReadStream().】