Merge pull request #2083 from consilience/9.0

[9.0] Using predefined offsets for API-driven server-side(ish) DataTables.

Author: yajra

src/CollectionDataTable.php

@@ -23,6 +23,13 @@ class CollectionDataTable extends DataTableAbstract
      */
     public $original;
 
+    /**
+     * The offset of the first record in the full dataset.
+     *
+     * @var int
+     */
+    private $offset = 0;
+
     /**
      * Can the DataTable engine be created with these parameters.
      *
@@ -136,7 +143,7 @@ function ($row) use ($column, $keyword, $regex) {
     public function paging()
     {
         $this->collection = $this->collection->slice(
-            $this->request->input('start'),
+            $this->request->input('start') - $this->offset,
             (int) $this->request->input('length') > 0 ? $this->request->input('length') : 10
         );
     }
@@ -313,4 +320,19 @@ protected function resolveCallbackParameter()
     {
         return $this;
     }
+
+    /**
+     * Define the offset of the first item of the collection with respect to
+     * the FULL dataset the collection was sliced from. It effectively allows the
+     * collection to be "pre-sliced".
+     *
+     * @param int $offset
+     * @return $this
+     */
+    public function setOffset(int $offset)
+    {
+        $this->offset = $offset;
+
+        return $this;
+    }
 }