Promises let you compose a program to eventually process a single result. They're oriented around a single event. Observables let you compose a program to proce

Promises let you compose a program to eventually process a single result. They're oriented around a single event. Observables let you compose a program to process a stream of values. In practice, there's an abstraction jump with observables. Promise compositions are usually built in response to an imperative action. Observables are built to replace imperative event handlers altogether.