Your environment has a non-standard
NODE_ENV value configured.
This may be by accident, so if you're unaware where the value is coming from, check the following:
.env*files in your project, if present
~/.bash_profile, if present
~/.zshrc, if present
The greater React ecosystem treats
NODE_ENV as a convention, only permitting three (3) values:
production: When your application is built with
development: When your application is run with
test: When your application is being tested (e.g.
Setting a non-standard
NODE_ENV value may cause dependencies to behave unexpectedly, or worse, break dead code elimination.
To fix this error, identify the source of the erroneous
NODE_ENV value and get rid of it: Next.js automatically sets the correct value for you.
If you need the concept of different environments in your application, e.g.
staging, you should use a different environment variable name like