Merge pull request #279 from natebird/order_nulls_last_new

Add "order nulls last" global and per column options

Author: n-rodriguez

lib/ajax-datatables-rails/config.rb

@@ -26,5 +26,6 @@ class Configuration
 
     config_accessor(:orm) { :active_record }
     config_accessor(:db_adapter) { :postgresql }
+    config_accessor(:nulls_last) { false }
   end
 end

lib/ajax-datatables-rails/datatable/column/order.rb

@@ -18,6 +18,11 @@ def sort_query
           custom_field? ? source : "#{table.name}.#{sort_field}"
         end
 
+        # Add option to sort null values last
+        def nulls_last
+          @view_column[:nulls_last] || (@options[:nulls_last] == 'true')
+        end
+
       end
     end
   end

lib/ajax-datatables-rails/datatable/simple_order.rb

@@ -12,7 +12,11 @@ def initialize(datatable, options = {})
       end
 
       def query(sort_column)
-        "#{sort_column} #{direction}"
+        if sort_nulls_last?
+          "CASE WHEN #{sort_column} IS NULL THEN 1 ELSE 0 END, #{sort_column} #{direction}"
+        else
+          "#{sort_column} #{direction}"
+        end
       end
 
       def column
@@ -33,6 +37,10 @@ def column_direction
         @options[:dir].upcase
       end
 
+      def sort_nulls_last?
+        column.nulls_last == true || AjaxDatatablesRails.config.nulls_last == true
+      end
+
     end
   end
 end

lib/ajax-datatables-rails/orm/active_record.rb

@@ -19,7 +19,7 @@ def sort_records(records)
           queries << order.query(column.sort_query) if column && column.orderable?
           queries
         end
-        records.order(sort_by.join(', '))
+        records.order(Arel.sql(sort_by.join(', ')))
       end
       # rubocop:enable Style/EachWithObject
 

spec/ajax-datatables-rails/datatable/column_spec.rb

@@ -10,13 +10,17 @@
     let(:column) { datatable.datatable.columns.first }
 
     before do
-      datatable.params[:columns] = {'0'=>{'data'=>'username', 'name'=>'', 'searchable'=>'true', 'orderable'=>'true', 'search'=>{'value'=>'searchvalue', 'regex'=>'false'}}}
+      datatable.params[:columns] = {'0'=>{'data'=>'username', 'name'=>'', 'searchable'=>'true', 'orderable'=>'true', 'search'=>{'value'=>'searchvalue', 'regex'=>'false'}, 'nulls_last'=>'true'}}
     end
 
     it 'should be orderable' do
       expect(column.orderable?).to eq(true)
     end
 
+    it 'should sort nulls last' do
+      expect(column.nulls_last).to eq(true)
+    end
+
     it 'should be searchable' do
       expect(column.searchable?).to eq(true)
     end

spec/ajax-datatables-rails/datatable/simple_order_spec.rb

@@ -2,12 +2,39 @@
 
 describe AjaxDatatablesRails::Datatable::SimpleOrder do
 
+  let(:view) { double('view', params: sample_params) }
+  let(:datatable) { ComplexDatatable.new(view).datatable }
   let(:options) { ActiveSupport::HashWithIndifferentAccess.new({'column' => '1', 'dir' => 'desc'}) }
-  let(:simple_order) { AjaxDatatablesRails::Datatable::SimpleOrder.new(nil, options) }
+  let(:simple_order) { AjaxDatatablesRails::Datatable::SimpleOrder.new(datatable, options) }
 
   describe 'option methods' do
     it 'sql query' do
       expect(simple_order.query('firstname')).to eq('firstname DESC')
     end
   end
+
+  describe 'option methods with nulls last' do
+    describe 'using global option' do
+      before { AjaxDatatablesRails.config.nulls_last = true }
+      after  { AjaxDatatablesRails.config.nulls_last = false }
+
+      it 'sql query' do
+        expect(simple_order.query('email')).to eq(
+          'CASE WHEN email IS NULL THEN 1 ELSE 0 END, email DESC'
+        )
+      end
+    end
+
+    describe 'using column option' do
+      let(:sorted_datatable) { DatatableOrderNullsLast.new(view).datatable }
+      let(:nulls_last_order) { AjaxDatatablesRails::Datatable::SimpleOrder.new(sorted_datatable, options) }
+
+      it 'sql query' do
+        expect(nulls_last_order.query('email')).to eq(
+          'CASE WHEN email IS NULL THEN 1 ELSE 0 END, email DESC'
+        )
+      end
+    end
+  end
+
 end

spec/ajax-datatables-rails/orm/active_record_sort_records_spec.rb

@@ -4,6 +4,7 @@
 
   let(:view) { double('view', params: sample_params) }
   let(:datatable) { ComplexDatatable.new(view) }
+  let(:nulls_last_datatable) { DatatableOrderNullsLast.new(view) }
   let(:records) { User.all }
 
   before(:each) do
@@ -44,4 +45,33 @@
     end
   end
 
+  describe '#sort_records with nulls last using global config' do
+    before { AjaxDatatablesRails.config.nulls_last = true }
+    after  { AjaxDatatablesRails.config.nulls_last = false }
+  
+    it 'can handle multiple sorting columns' do
+      # set to order by Users username in ascending order, and
+      # by Users email in descending order
+      datatable.params[:order]['0'] = { column: '0', dir: 'asc' }
+      datatable.params[:order]['1'] = { column: '1', dir: 'desc' }
+      expect(datatable.sort_records(records).to_sql).to include(
+        'ORDER BY CASE WHEN users.username IS NULL THEN 1 ELSE 0 END, users.username ASC, ' +
+        'CASE WHEN users.email IS NULL THEN 1 ELSE 0 END, users.email DESC'
+      )
+    end
+  end
+  
+  describe '#sort_records with nulls last using column config' do
+    it 'can handle multiple sorting columns' do
+      # set to order by Users username in ascending order, and
+      # by Users email in descending order
+      nulls_last_datatable.params[:order]['0'] = { column: '0', dir: 'asc' }
+      nulls_last_datatable.params[:order]['1'] = { column: '1', dir: 'desc' }
+      expect(nulls_last_datatable.sort_records(records).to_sql).to include(
+        'ORDER BY users.username ASC, ' +
+        'CASE WHEN users.email IS NULL THEN 1 ELSE 0 END, users.email DESC'
+      )
+    end
+  end
+
 end

spec/spec_helper.rb

@@ -82,4 +82,5 @@
 load File.dirname(__FILE__) + '/support/datatable_cond_numeric.rb'
 load File.dirname(__FILE__) + '/support/datatable_cond_proc.rb'
 load File.dirname(__FILE__) + '/support/datatable_cond_string.rb'
+load File.dirname(__FILE__) + '/support/datatable_order_nulls_last.rb'
 require File.dirname(__FILE__) + '/support/test_models.rb'

spec/support/datatable_order_nulls_last.rb

@@ -0,0 +1,5 @@
+class DatatableOrderNullsLast < ComplexDatatable
+  def view_columns
+    super.deep_merge(email: { nulls_last: true })
+  end
+end

spec/support/test_helpers.rb

@@ -82,7 +82,7 @@ def get_raw_records
     User.all
   end
 end
-
+ 
 class ComplexDatatableArray < ComplexDatatable
   def data
     records.map do |record|