Warnings
Table of contents
Warnings
Warnings In Fastify
Fastify utilizes Node.js's warning event
API to notify users of deprecated features and known coding mistakes. Fastify's
warnings are recognizable by the FSTWRN
and FSTDEP
prefixes on warning
code. When encountering such a warning, it is highly recommended that the
cause of the warning be determined through use of the
--trace-warnings
and
--trace-deprecation
flags. These will produce stack traces pointing out where the issue occurs
in the application's code. Issues opened about warnings without including
this information may be closed due to lack of information.
In addition to tracing, warnings can also be disabled. It is not recommended to disable warnings as a matter of course, but if necessary, they can be disabled by using any of the following methods:
- setting the
NODE_NO_WARNINGS
environment variable to1
- passing the
--no-warnings
flag to the node process - setting 'no-warnings' in the
NODE_OPTIONS
environment variable
For more information on how to disable warnings, see node's documentation.
However, disabling warnings is not recommended as it may cause potential problems when upgrading Fastify versions. Only experienced users should consider disabling warnings.
Fastify Warning Codes
Code | Description | How to solve | Discussion |
---|---|---|---|
FSTWRN001 | The specified schema for a route is missing. This may indicate the schema is not well specified. | Check the schema for the route. | #4647 |
FSTWRN002 | The %s plugin being registered mixes async and callback styles, which will result in an error in fastify@5 . | Do not mix async and callback style. | #5139 |
Fastify Deprecation Codes
Deprecation codes are further supported by the Node.js CLI options:
Code | Description | How to solve | Discussion |
---|