fs.writeFile with callback will log: DeprecationWarning: Calling an asynchronous function without callback is deprecated.

[rokyed]

NODE:

node.js v6.7.0

SYSTEM:

Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 2
Core(s) per socket: 2
Socket(s): 1
NUMA node(s): 1
Vendor ID: AuthenticAMD
CPU family: 21
Model: 19
Model name: AMD A8-6500 APU with Radeon(tm) HD Graphics
Stepping: 1
CPU MHz: 1700.000
CPU max MHz: 3500.0000
CPU min MHz: 1700.0000
BogoMIPS: 6999.72
Virtualization: AMD-V
L1d cache: 16K
L1i cache: 64K
L2 cache: 2048K
NUMA node0 CPU(s): 0-3

OS:

Linux my-name 4.4.0-67-generic #88-Ubuntu SMP Wed Mar 8 16:34:45 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

ERROR:

DeprecationWarning: Calling an asynchronous function without callback is deprecated.

WHEN:

// callback and scope are provided before
fs.writeFile(fileName, myString, (err) => {
	if (err) throw err;

	console.log('=> done  ' + fileName);
	callback.apply(scope, [fileName]);
});
// logically the code follows the structure but names and information are modified due to NDA.

[cjihrig]

FWIW, can't reproduce on macOS.

const fs = require('fs');

fs.writeFile(__dirname + '/blah.out', 'hello', (err) => {
	if (err) throw err;
	console.log('done');
});

$ node -v
v6.7.0
$ node foo.js 
done
$ cat blah.out 
hello

[vsemozhetbyt]

@rokyed I also can't reproduce on Windows:

'use strict';

const fs = require('fs');

const fileName = 'test.txt'
const myString = 'abc';
const scope = {};
const callback = () => {};

fs.writeFile(fileName, myString, (err) => {
  if (err) throw err;

  console.log('=> done  ' + fileName);
  callback.apply(scope, [fileName]);
});

> node.exe -v
v6.7.0

> node.exe test.js
=> done  test.txt

> cat test.txt
abc

Are you sure the fs.writeFile() produces this error? Could you provide the error stack trace and a minimal but complete code to reproduce?

[silverwind]

Pretty sure the warning isn't happening in the provided code sample. If you have better standalone example, please post it and we'll reopen.