In this chapter, we extensively covered the JavaScript API and the Locker Service security model for Lightning Components. Locker Service acts as a virtual browser, with security built into it. Locker Services are an important part of the Salesforce security model, preventing components from accessing data from other components in different namespaces.
In the next chapter, we will look at how to make components talk to each other via events. We will explore application and component events in detail.