ExperimentalWarning: The fs.promises API is experimental

Question

I am new to node and npm and trying to understand AutoRest.

When I type

autorest --list-available

into powershell ISE I get

AutoRest code generation utility [version: 2.0.4262; node: v10.1.0]
(C) 2018 Microsoft Corporation.
https://aka.ms/autorest
autorest : (node:12580) ExperimentalWarning: The fs.promises API is experimental
At line:1 char:1
+ autorest --list-available
+ ~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: ((node:12580) Ex...is experimental:String) [], RemoteExc 
   eption
    + FullyQualifiedErrorId : NativeCommandError

 Extension Name                 Version       

 @microsoft.azure/autorest-core 2.0.4278       
 @microsoft.azure/autorest-core 2.0.4277       
 @microsoft.azure/autorest-core 2.0.4276       
 @microsoft.azure/autorest-core 2.0.4275       
 @microsoft.azure/autorest-core 2.0.4274       
 @microsoft.azure/autorest-core 2.0.4272       
 @microsoft.azure/autorest-core 2.0.4271       
 @microsoft.azure/autorest-core 2.0.4269       
 @microsoft.azure/autorest-core 2.0.4263       
 @microsoft.azure/autorest-core 2.0.4262       
Failure:
TypeError: volume[member].bind is not a function
TypeError: volume[member].bind is not a function
    at patchFilesystem 
(C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:277:43)
    at C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:281:18
    at Object.global.staticloader.undo 
(C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:163:7)
    at process.exit.n [as exit] 
(C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:170:27)
    at main (C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\app.js:153:21)
    at process._tickCallback (internal/process/next_tick.js:68:7)
(node:12580) UnhandledPromiseRejectionWarning: Error: EBADF: bad file descriptor, close
    at Object.fs.closeSync (fs.js:529:3)
    at StaticVolumeFile.shutdown 
(C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:352:10)
    at StaticFilesystem.shutdown 
(C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:406:17)
    at process.exit.n [as exit] 
(C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\static-loader.js:169:11)
    at main (C:\Users\kirst\AppData\Roaming\npm\node_modules\autorest\dist\app.js:239:17)
    at process._tickCallback (internal/process/next_tick.js:68:7)
(node:12580) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated 
either by throwing inside of an async function without a catch block, or by rejecting a promise 
which was not handled with .catch(). (rejection id: 1)
(node:12580) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the 
future, promise rejections that are not handled will terminate the Node.js process with a non-zero

what is happening? exit code.

It gives you an error code: `node:12580`. Additionally, you can do `$Error[0] | Format-List -Property * -Force` to see the full error record for your command. — Maximilian Burszley, May 21 '18 at 14:28
It looks like the `AutoRest` package isn't following best-practices and leaving unhandled errors. — Maximilian Burszley, May 21 '18 at 14:30

score 29 · Answer 1 · answered Apr 06 '20 at 21:10

29

Updating to the latest node version (v12.6+) removes the warning.

answered Apr 06 '20 at 21:10

XCS

27,244
26
101
151

score 21 · Answer 2 · answered Oct 21 '18 at 13:06

21

Yes, you can safely ignore this warning. If you want to suppress it (and all warnings), run your script with node --no-warnings instead of node.

In your example:

node --no-warnings `which autorest`

answered Oct 21 '18 at 13:06

Ore4444

9,119
2
23
29

14

Absolutely shocking that in almost 2019 their file system support is still "experimental". – user9993 Dec 24 '18 at 19:06
14

The filesystem API itself isn't experimental - the promise-based one is (because it is relatively new and its public interface might change). – Maël Nison Jan 10 '19 at 16:57
so is it safe to use at production? Any alternative for this? – Sunil Garg Apr 09 '19 at 09:06
1

Safe to use but I'm looking for a way to disable it without specifying startup param every time. – user0103 May 24 '19 at 14:19
2

This warning disappears with most recent node version (tried with v12.6.0) – Tdy Jul 05 '19 at 14:17

Umar Asghar · Answer 3 · 2020-07-30T04:23:25.783

15

I was at node@^10.15.1 which is an older version so I update it to 12.16.1 or 12.16.2 and it got fixed.

edited Jul 30 '20 at 04:23

answered Apr 13 '20 at 17:17

Umar Asghar

3,808
1
36
32

score 9 · Accepted Answer · answered May 21 '18 at 14:30

9

The module autorest uses new fs syntax, that instead of callbacks uses Promises. This is however not yet stable and therefore is the warning. Nothing really to worry about, unless you want to use it in production. But even then, as long as you update autorest with node together no problems should occur.

As for the error, it may be something in your configs. Try to make minimal error sample and post an issue to autorest git.

answered May 21 '18 at 14:30

Akxe

9,694
3
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As an added note, since (s?)he is launching it from `powershell`, use `$ErrorActionPreference = 'SilentlyContinue'` to suppress the error. `powershell` has both terminating and non-terminating errors. Alternatively, `2>$null` at the end of the command. – Maximilian Burszley May 21 '18 at 14:33

score 8 · Answer 5 · answered Jul 02 '20 at 11:26

8

I Was at node@10.16.1 and I update it to 12.18.2and it got fixed!

answered Jul 02 '20 at 11:26

Consule

1,059
12
12

score 4 · Answer 6 · answered Jun 10 '21 at 13:50

4

It might have because you have updated the npm version but not the node version. I updated the npm version from 6.3.0 to 7.16.0 [latest at this time], but was still using 11.3.0 for the node. To fix this version, I updated node to the latest LTS, i.e. 14.17.0 [LTS at this time].

nvm install 14.17.0 // Check for the LTS
nvm use 14.17.0
nvm alias default 14.17.0

answered Jun 10 '21 at 13:50

Parth Mansata

145
1
7

This worked great for me. I substituted with 14.18.1 since that was the latest when I found my way to this answer. – benhorgen Nov 13 '21 at 06:08

score 2 · Answer 7 · answered Aug 02 '20 at 17:13

2

In Angular 10 that's just a warning when serving your code, which you can ignore as of today.

answered Aug 02 '20 at 17:13

Daniel Danielecki

8,508
6
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2

Why can we ignore it? I can't find anything else regarding this warming besides your post. – Norbert Huurnink Aug 10 '20 at 13:04
@Noppey it simply didn't affect my build, that's my personal conclusion if you're working with Angular. – Daniel Danielecki Aug 10 '20 at 17:13

ExperimentalWarning: The fs.promises API is experimental

7 Answers7