What is locker services in lightning ?

Sometime in June, when we were logging into Salesforce, we were getting a warning which says "Lightning Locker Service will be enforced in June". If you have too many lightning components in your Salesforce org and they are being used by live users (either application or component), then you need to tighten your belts because those might stop working due to some locker issue by the update of lightning locker services when the locker services are fully enforced by Salesforce.

                           

What is Locker Services?

LockerService is a powerful security architecture for Lightning components. LockerService enhances security by isolating Lightning components in their own namespace. LockerService also promotes best practices that improve the supportability of your code by only allowing access to supported APIs and eliminating access to non-published framework internals.

Things will have the affect by Locker Services :

LockerService enforces security and best practices for custom Lightning components you use in:

• Lightning Experience
• Salesforce1
• Lightning Communities
• Standalone apps that you create
• Any other app where you can add a custom Lightning component, such as Salesforce Console in Lightning Experience
• Lightning Out

Things will not have the affect from Locker Sevices : 

Locker service doesn’t affect the following except for usage of Lightning components in Visualforce in these contexts:

• Salesforce Classic
• Visualforce-based communities
• Any apps for Salesforce Classic, such as Salesforce Console in Salesforce Classic

Locker service is intended to use following technologies and techniques : 

To prevent from : 

• Components from causing XSS and similar security issues
• Components from reading other component’s rendered data without any restrictions
• Components from calling undocumented/private APIs

To Enable : 

• Cool new features like client-side API versioning similar to REST API versioning*
• Faster security review
• Better and more secure JS development practices
• Running 3rd party JS frameworks like React, Angular and so on*
• Easily adding or removing new security features and policies

To get more detailed description about locker services, click here 

Source: developer.salesforce.com

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