Question

What are the differences between promises and observables in Javascript?

Answer 1

Some of the major difference in a tabular form

Promises	Observables
Emits only a single value at a time	Emits multiple values over a period of time(stream of values ranging from 0 to multiple)
Eager in nature; they are going to be called immediately	Lazy in nature; they require subscription to be invoked
Promise is always asynchronous even though it resolved immediately	Observable can be either synchronous or asynchronous
Doesn't provide any operators	Provides operators such as map, forEach, filter, reduce, retry, and retryWhen etc
Cannot be canceled	Canceled by using unsubscribe() method