Given a partial view that simply turns a given ruby object into JSON, shouldn't render 'ajax/object' and render json: @object deliver the same result?
ajax/object.json.erb:
<%= @object.to_json %>
@object:
{"id":1}
Because they don't.
render 'ajax/object' results in XMLHttpRequest.response === null and the rendered view being sent as: (Snippet taken from saved .har file)
"content": {
"size": 18,
"mimeType": "application/json",
"compression": -11,
"text": "{"id":1}"
},
render json: @object, on the other hand, results in the behavior I expected: XMLHttpRequest.response === ("id": 1)
So my question is: Is this difference in rendering behavior a bug and, if not, what is the purpose of render 'ajax/object''s rendering behavior?
The issue here is that the string created in the template is HTML escaped.
While you could fix it with:
<%= raw( @object.to_json ) %>
Using a template is stupid and silly in the first place. Rails has to lookup the template by traversing a tree of possible files and then has to parse ERB and create a string buffer etc. This is just ridiculously inefficient for something which can be handled by passing an object to a JSON encoder.