node.js - _read() 的节点可读流何时调用

Answer 1

If I don't add on('data'） listerner, the _read() will not be called. Why?

The stream is paused. Assuming you are using a recent version of node.

https://nodejs.org/api/stream.html#stream_two_modes

All Readable streams begin in paused mode but can be switched to flowing mode in one of the following ways:

Adding a 'data' event handler.

Calling the stream.resume() method.

Calling the stream.pipe() method to send the data to a Writable.

BTW, to create a readable, check noms or mississippi.from