Component interaction with BehaviorSubject

To update the current weather information, we need the citySearch component to interact with the currentWeather component. There are four main techniques to enable component interaction in Angular:

• Global events
• Parent components listening for information bubbling up from children components
• Sibling, parent, or children components within a module that works off of similar data streams
• Parent components passing information to children components

Let’s explore them in detail in the following sections.

Global events

This technique has been leveraged since the early days of programming in general. In JavaScript, you may have achieved this with global function delegates or jQuery’s event system. In AngularJS, you may have created a service and stored variables within it.

In Angular, you can still create a root-level service, store values in it, use Angular’s EventEmitter class...