We help IT Professionals succeed at work.
Get Started

undefined method for nil:NilClass

Andrew Chipman
on
186 Views
Last Modified: 2019-11-30
In ruby on rails I'm trying to render a json file that will map each comment to a review. Each Review has many comments but each comment belongs to a review.

Here is my controller to generate a json file.

`  reviews: @ship.reviews.preload(:user_profile).map do |review|
        {
          id: review.id,
          body: review.body,
          rating: review.rating,
          user_profile: review.user_profile,
          comments: @review.comment.preload(:comment).map do |comment|
            {
              id: comment.id,
              body: comment.body,
              user_profile: comment.user_profile_id,
            }
          end
        }

Open in new window


Here is the comment model

class Comment < ApplicationRecord
  belongs_to :user_profile
  belongs_to :review
end

Open in new window


Here is the review.rb model

`class Review < ApplicationRecord
  belongs_to :user_profile
  belongs_to :ship
  has_many :comments
  has_many :helpfuls
end

Open in new window


However my json file returns an error: undefined method `comment' for nil:NilClass on this line:

comments: @review.comment.preload(:comment).map do |comment|

Open in new window

Comment
Watch Question
This problem has been solved!
Unlock 1 Answer and 1 Comment.
See Answer
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant

An Experts Exchange subscription includes unlimited access to online courses.

Get Started
Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE