Question

does anybody know the difference between the object on the initial show.html.erb in Rails and the index.html.erb? The reason I’m asking is because I’m using the javascript library d3.js and for that I need a json-object. In all index.html.erb I can create them with calling:
<% @commits.to_json %> but if I try to use that statement in any show.html.erb the browser tells me that the result is just an object (seems not to be a json) so that I later can’t call forEach (that I need to call).

Thanks in advance!

Ok, for a better understanding I append more code:

<%= javascript_tag do %>

d3.json('<% @commit.jobs.to_json %>', 
            function(data){


      var margin = {top: 20, right: 80, bottom: 30, left: 50},
          width = 960 - margin.left - margin.right,
          height = 500 - margin.top - margin.bottom;

      var format = d3.time.format("%Y-%m-%dT%H:%M:%SZ");

      //parse time format correct
      data.forEach(function(d) {
          console.log(d.finished_at);
          d.finished_at = format.parse(d.finished_at);
          console.log(d.finished_at);
        });

   //more code!     


<% end %>

The problem is, I have a commit object in show.html.erb that has belonging jobs and now I want to visualize the belonging jobs with d3.js. I tested if this: @commit.jobs.to_json creates a valid json and it does! But the console throws an error: Uncaught TypeError: Object #<Object> has no method 'forEach'

What am I doing wrong?

Answer 1

In show you usually have only one @commit that you are showing.

In index you usually have all @commits as an array of objects.

def index
   @commits = Commit.all # all
end

def show
   @commit = Commit.find(params[:id]) # only one
end

if you want all commits in the show.html.erb do <%= Commit.all.to_json %>

So there are technically no differences between the objects based on the view they are in. They just mean different (@commit,@commits) things based on how they got initialized in the method before calling the view.