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Javascript - Difference between Promises and Observables


Both Promises and Observables will help us work with the asynchronous functionalities in JavaScript.

The main differences between them are listed below:

Promise:
  • Promises are values that will resolve in asynchronous ways like http calls
  • They have one pipeline
  • They are usually only use with async data return
  • They are not easy to cancel
Observable:
  • Observables deal with a sequence of asynchronous events
  • They are cancellable
  • They are retriable by nature such as retry and retryWhen
  • They stream data in multiple pipelines
  • They have array-like operations like map, filter etc.
  • They can be created from other sources like events
  • They are functions, which could be subscribed later on