perf: Optimise Rendering

- optimise get_children function

- use promises instead of callbacks

- optimise selectors

- use const wherever possible

- use pure js instead of jquery for connectors for faster rendering

erpnext/hr/page/organizational_chart/organizational_chart.py

@@ -2,33 +2,25 @@ from __future__ import unicode_literals
 import frappe
 
 @frappe.whitelist()
-def get_children(parent=None, company=None, exclude_node=None, is_root=False, is_tree=False, fields=None):
+def get_children(parent=None, company=None):
 
 	filters = [['status', '!=', 'Left']]
 	if company and company != 'All Companies':
 		filters.append(['company', '=', company])
 
-	if not fields:
-		fields = ['employee_name as name', 'name as id', 'reports_to', 'image', 'designation as title']
-
-	if is_root:
-		parent = ''
-
-	if exclude_node:
-		filters.append(['name', '!=', exclude_node])
-
 	if parent and company and parent != company:
 		filters.append(['reports_to', '=', parent])
 	else:
 		filters.append(['reports_to', '=', ''])
 
-	employees = frappe.get_list('Employee', fields=fields,
-		filters=filters, order_by='name')
+	employees = frappe.get_list('Employee',
+		fields=['employee_name as name', 'name as id', 'reports_to', 'image', 'designation as title'],
+		filters=filters,
+		order_by='name'
+	)
 
 	for employee in employees:
-		is_expandable = frappe.get_all('Employee', filters=[
-			['reports_to', '=', employee.get('id')]
-		])
+		is_expandable = frappe.db.count('Employee', filters={'reports_to': employee.get('id')})
 		employee.connections = get_connections(employee.id)
 		employee.expandable = 1 if is_expandable else 0