A way to connect a producer of values to observers of those values

A way to notify one or more observers of multiple values emitted over time

next, subscribe, unsubscribe

notify, subscribe, delete

By creating a new instance of an observable and passing it through the constructor

By calling the next method

To call the next method on an observer when a new value is produced

To produce values to pass to an observer

Cold observables only produce one value, hot observables can produce multiple values over time

Hot observables are more performant than cold observables

Hot/multicast observable

Cold/unicast observable

By calling the next method from outside of the observable

By supplying a function that accept an observer to the next method

By supplying a function that accepts an observer when creating an new instance of a Subject

By supplying a function that accept an observer to the next method

Observable operators and subject operators

Hot operators and cold operators

Subscribes to an observable and returns a new observable

Modifies an observable stream in some way