Heroku log warning "(node) sys is deprecated. Use util instead" when script runs

Question

I have deployed a node script in heroku to be run by a scheduler. But when the script runs I see a warning in the logs.

Dec 07 11:01:10 xxx heroku/scheduler.3255 Starting process with command `node bin/script` 
Dec 07 11:01:13 xxx app/scheduler.3255:  (node) sys is deprecated. Use util instead. 

I have not declared a engine section in my package.json.

Is a problem with the node version? How can I avoid this warning?

Thanks!

Answer 1

This is happening because (obviously) 'sys' has been deprecated and replaced by 'util'.

If you are not using 'sys' directly (search your codebase for something like require('sys') ) then one of the modules that you depend on (or its dependencies) might be.

To find the offending module do an npm install on your project and then grep for require('sys') (or with double quotes) to see if you can find the module. Example grep command:

grep -r "require('sys')" .

If you really want that warning to go away and it's in a dependency or sub-dependency then you have a couple of choices:

1. Replace the module that's using sys with one that isn't yet provides the same functionality. (Check that there isn't a more recent version of the module that's addressed this issue.)
2. Submit a Pull Request fixing the issue in the module.