node.js - nodejs using pm2 and debug ，all the log output by the ‘debug’ module all to the stderr ,why? -

pm2 -version:0.12.1;debug -version:2.1.0

code:

 debug("send data client success! length " + buf.length+" bytes!"); 

pm2 logs:

[1_control-15 (err)] tue, 16 dec 2014 12:36:50 gmt [1_control] client.ts send data client success! length 100 bytes!  [1_control-15 (err)] tue, 16 dec 2014 12:36:50 gmt [1_control]n client.ts send data client success! length 135 bytes! 

please help.

not sure if question still relevant, official documentation says, can override behavior this:

  var debug = require('debug');   var error = debug('app:error');    // default stderr used    error('goes stderr!');    var log = debug('app:log');   // set namespace log via console.log    log.log = console.log.bind(console); // don't forget bind console!    log('goes stdout');   error('still goes stderr!');    // set output go via console.info    // overrides per-namespace log settings    debug.log = console.info.bind(console);   error('now goes stdout via console.info');   log('still goes stdout, via console.info now'); 

`