Alexandre Calaça
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Rails: NameError (uninitialized constant UserSerializer) error message

How to solve fast_jsonapi serializer error?

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Alexandre Calaça
·Jul 27, 2022·

2 min read

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Table of contents

  • Introduction
  • Issue
  • Tests
  • Solution
  • Conclusion

Introduction

The fast_jsonapi is a a lightning fast JSON:API serializer for Ruby Objects. Its github page can be accessed here.

The project is no longer maintained, but you might end up using it in some applications.

Issue

This is the usual error message:

NameError (uninitialized constant UserSerializer)

image.png

Tests

None of the following tests worked:

  • Leave terminal and open it again;
  • Open a new tab;
  • Open the terminal on VS Code;
  • Open the terminal on Linux console;
  • Reload! Rails console;

Solution

For me, it worked to stop spring, which is a Rails application preloader.

  1. Exit Rails console
    exit
    
  2. Stop the spring Rails application preloader
    spring stop
    
    By the way, you can see all the available spring commands by using help
    spring help
    
  3. Enter Rails console again
    rails c
    
    or
    rails console
    
  4. Run the test command Here, I tried:
    UserSerializer.new( User.first ).serializable_hash
    

image.png or just type

UserSerializer

It'll return the class itself

image.png

  1. spring is still working
    In case you're a spring freak (Just kidding lol), spring is fine.

Leave the terminal

exit

and there you go, spring is fine

spring status

image.png

Conclusion

That's all. Hope you guys liked it. Let me know if you need any help.

 
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