• Version: v9.3.0
• Platform: Darwin 16.7.0 Darwin Kernel Version 16.7.0: Thu Jan 11 22:59:40 PST 2018; root:xnu-3789.73.8~1/RELEASE_X86_64 x86_64
• Subsystem:

Execute code at node command line.

const cp = require('child_process'); const child = cp.exec('pwd', {encoding: 'invalid'}, (err, stdout, stderr) => { console.log('callback', err) console.log('callback', typeof stdout, stdout) }) child.stdout.setEncoding('utf8') child.stdout.on('data', function (v) { console.log(typeof v, v) })

The output is :

buffer.js:475 throw new errors.TypeError( ^ TypeError [ERR_INVALID_ARG_TYPE]: The "list" argument must be one of type Array, Buffer, or Uint8Array at Function.concat (buffer.js:475:13) at ChildProcess.exithandler (child_process.js:259:23) at ChildProcess.emit (events.js:159:13) at maybeClose (internal/child_process.js:943:16) at Socket.stream.socket.on (internal/child_process.js:363:11) at Socket.emit (events.js:159:13) at Pipe._handle.close [as _onclose] (net.js:568:12) 

Is this a bug in nodejs?

BTW: The issue finder is @xqin

There didn't trigger the exception if use cp.exec('pwd', {encoding: 'invalid'}) without the callback.

@xqin has a new idea that whether need bind listener on stdout and stderr when user not pass the callback param. The source code at: https://github.com/nodejs/node/blob/master/lib/child_process.js#L322-L358