add posibility to block back || forward on change date

Author: bodasia

DateTime.d.ts

@@ -102,12 +102,12 @@ declare namespace ReactDatetimeClass {
          Callback trigger when the user navigates to the previous month, year or decade.
          The callback receives the amount and type ('month', 'year') as parameters.
          */
-        onNavigateBack?: (amount: number, type: string) => void;
+        onNavigateBack?: (amount: number, type: string, curDate: any) => void;
         /*
          Callback trigger when the user navigates to the next month, year or decade.
          The callback receives the amount and type ('month', 'year') as parameters.
          */
-        onNavigateForward?: (amount: number, type: string) => void;
+        onNavigateForward?: (amount: number, type: string, curDate: any) => void;
         /*
          The default view to display when the picker is shown. ('years', 'months', 'days', 'time')
          */

DateTime.js

@@ -260,16 +260,18 @@ var Datetime = createClass({
 	subtractTime: function( amount, type, toSelected ) {
 		var me = this;
 		return function() {
-			me.props.onNavigateBack( amount, type );
-			me.updateTime( 'subtract', amount, type, toSelected );
+			if (me.props.onNavigateBack( amount, type, me.state.date )) {
+        me.updateTime( 'subtract', amount, type, toSelected );
+			}
 		};
 	},
 
 	addTime: function( amount, type, toSelected ) {
 		var me = this;
 		return function() {
-			me.props.onNavigateForward( amount, type );
-			me.updateTime( 'add', amount, type, toSelected );
+      if (me.props.onNavigateForward( amount, type, me.state.date )) {
+        me.updateTime('add', amount, type, toSelected);
+      }
 		};
 	},
 
@@ -465,8 +467,8 @@ Datetime.defaultProps = {
 	onBlur: function() {},
 	onChange: function() {},
 	onViewModeChange: function() {},
-	onNavigateBack: function() {},
-	onNavigateForward: function() {},
+	onNavigateBack: function() { return true; },
+	onNavigateForward: function() { return true; },
 	timeFormat: true,
 	timeConstraints: {},
 	dateFormat: true,