Added support for sort column

lib/mongoose-datatables.js

@@ -25,26 +25,45 @@ function dataTablesPlugin (schema, options) {
     var columns = params.columns || [];
     var formatter = params.formatter
 
+    var findGlobal = []
     if (search && search.value && search.fields && search.fields.length) {
       var searchQuery = {
         '$regex': search.value,
         '$options': 'i'
       }
-
-      if (search.fields.length == 1) {
-        find[search.fields[0]] = searchQuery
-      } else if(search.fields.length > 1) {
-        if (!find.$or) {
-          find.$or = []
-        }
-        search.fields.forEach(function (el){
+
+      if(search.fields.length >= 1) {
+        search.fields.forEach(function (field){
           var obj = {}
-          obj[el] = searchQuery
-          find.$or.push(obj)
+          obj[field] = searchQuery
+          findGlobal.push(obj)
         })
       }
     }
 
+    var findColumn = []
+    if (columns && columns.length>=1) {
+      columns.forEach(function(col){
+        if (col.value) {
+          col.fields.forEach(function (field){
+            var obj = {}
+            obj[field] = col.value
+            findColumn.push(obj)
+          })
+        }
+      })
+    }
+
+    if (findGlobal.length>0 && findColumn.length>0) {
+      find.$and = [];
+      find.$and.push({$or:findGlobal})
+      find.$and.push({$and:findColumn})
+    } else if (findGlobal.length>0) {
+      find = {$or:findGlobal}
+    } else if (findColumn.length>0) {
+      find = {$and:findColumn}
+    }
+
     if (order && columns) {
       const sortByOrder = order.reduce((memo, ordr) => {
         const column = columns[ordr.column];