How use a ruby code inside the javascript

Question

I am implementing a live search with a drop down containing multiple fields to filter through.It starts with only one search field, a drop down to select what to be searched for and a button to add more filters, when the user click the button, it generate a new field like this:

This image sample was done hard coded with the html inside the JavaScript. The problem is that I will use it in a lot of views so I need it to be dynamic as the code I previously done with Ruby to generate the first search field. I tried doing this way, but no success was achieved.

live_search.js.erb

$(function () {

    function search() {
        $.get(window.location.href, { object_columns: $("select#object_columns").val(), search: $("#search").val() }, null, "script");
    };

    $("select#object_columns").change(search);
    $("input#search").keyup(search);

    $('button').on('click',function(){
      column = "<%= j render 'shared/search_engine' %>";
      $('#search-form').after(column);
    });
});

search_engine.html.erb

<div id="search-form">
  <%= form_tag do %>
  <% valid_column_names = target.column_names.reject{|r| r == "created_at" || r == "updated_at" || r == "slug"} %>
  <%= select_tag :object_columns, options_for_select(valid_column_names) %>
  <%= text_field_tag :search, '', autocomplete: :off %>
  <% end %>
  <%= button_tag "+" %>
</div>

I even tried to call the "search-form" in the JavaScript to replicate the code when the button was clicked but I read that it is not possible.

EDIT

I made some changes as @ppascualv suggested, but I still can't render and add another "search_engine" when I click the button. I am getting an error saying undefined method 'render'.

live_search.js.erb

$(function () {

    function search() {
        $.get(window.location.href, { object_columns: $("select#object_columns").val(), search: $("#search").val() }, null, "script");
    };

    $("select#object_columns").change(search);
    $("input#search").keyup(search);

    $('button').on('click',function(){
      $('button').append("<%= escape_javascript(render @search_engine) %>");
    });
});

search_engine.html.erb

<div id="search-form">
  <%= form_tag({controller: "house_activities", action: "index"}, method: "get", remote: true) do %>
  <%  valid_column_names = HouseActivity.column_names.reject{|r| r == "created_at" || r == "updated_at" || r == "slug"} %>
  <%= select_tag :object_columns, options_for_select(valid_column_names) %>
  <%= text_field_tag :search, '', autocomplete: :off %>
  <% end %>
  <%= button_tag "+" %>
</div>

house_activities_controller.rb

class HouseActivitiesController < ApplicationController
  before_action :set_house_activity, only: [:show, :edit, :update, :destroy]

  def index
    @house_activities = HouseActivity.page(params[:page]).per(5).search_for(params[:object_columns], params[:search])
    respond_to do |format|
      format.js
      format.html
    end
  end
end

Answer 1

I was able to solve my problem. I discovered that you can't render things in assets and you can't use ruby inside a JavaScript file. I did some workaround and got it done, I included the JavaScript code inside the html.erb file using the <script> JavaScript code </script> syntax as shown here:

<script type="text/javascript">

  column =
  '<%= form_tag({controller: "people", action: "index"}, method: "get", remote: true) do %>' +
  '<%  valid_column_names = Person.column_names.reject{|r| r == "created_at" || r == "updated_at" || r == "slug"} %>' +
  '<%= j (select_tag :object_columns, options_for_select(valid_column_names)) %>' +
  '<%= text_field_tag :search, '', autocomplete: :off %>' +
  '<% end %>';

  $('button').on('click',function(){
    $('button').after(column);
  });

</script>

Because the select_tag ruby line generated a sentence with lots of quotation marks, the j used is the same as escape_javascript and it is used to format a sentence so the JavaScript can read it properly.

Answer 2

You could do something like:

search_engine.html.erb

<%= form_tag(target_path, method: :get) do %>
    <%= text_field_tag :query, nil, placeholder: "Search by column names...", class: "form-control search-form" %>
<% end %>

live_search.js

$(document).on("change", ".search-form", function() {
    return $(this).parents("form").submit();
});

Then in your target model, you could add a search scope to make it dynamic.

target.rb

class Target < ActiveRecord::Base
    scope :search, -> (query) {
        return if query.blank?;
        where("target.column_name1 ILIKE :query or target.column_name2 ILIKE :query or target.column_name3 ILIKE :query", query: "%#{query}%") 
    }
end

And in your targets_controller.rb

class TargetsController < ApplicationController
    def search_engine
        @targets = Target.search(params[:query])
    end
end

Answer 3

You should take a look at Javascript with Rails, for achive your proposit you will need to create a controller that responds with your js.erb, and this action should be called from a link with data-remote=true or from ajax.