Set nesting depth for leaf rows when rows are grouped

useGroupBy doesn't set nesting depth for leaf rows like in v6, so
leaf rows all had depth = 0 previously.

Author: glin

srcjs/__tests__/Reactable.v2.test.js

@@ -5676,6 +5676,28 @@ describe('grouping and aggregation', () => {
     ])
   })
 
+  it('leaf rows should have a nesting depth > 0', () => {
+    const props = {
+      data: { a: ['a', 'a', 'b'], b: [1, 2, 3], c: ['x', 'x', 'x'], d: [1, 2, 3] },
+      columns: [
+        { name: 'col-a', accessor: 'a' },
+        {
+          name: 'col-b',
+          accessor: 'b',
+          cell: cellInfo => cellInfo.depth,
+          aggregated: cellInfo => cellInfo.depth,
+          className: 'col-b'
+        },
+        { name: 'col-c', accessor: 'c' },
+        { name: 'col-d', accessor: 'd' }
+      ],
+      pivotBy: ['c', 'a'],
+      defaultExpanded: true
+    }
+    const { container } = render(<Reactable {...props} />)
+    expect(getCellsText(container, '.col-b')).toEqual(['0', '1', '2', '2', '1', '2'])
+  })
+
   it('aggregated cell formatting', () => {
     const props = {
       data: { a: ['a', 'a', 'b'], b: [1, 2, 3], c: ['x', 'x', 'x'], d: [1, 2, 3] },

srcjs/useGroupBy.js

@@ -1,6 +1,7 @@
 // useGroupBy hook modified to:
 // - Pass row objects and aggregated row objects to aggregate functions
 // - Include groupBy columns in aggregations
+// - Set nesting depth for leaf rows
 
 import React from 'react'
 import {
@@ -285,6 +286,10 @@ function useInstance(instance) {
     const groupUpRecursively = (rows, depth = 0, parentId) => {
       // This is the last level, just return the rows
       if (depth === existingGroupBy.length) {
+        // Set nesting depth for leaf rows
+        rows.forEach(row => {
+          row.depth = depth
+        })
         return rows
       }