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Javascript: Promise

Source: https://www.geeksforgeeks.org/javascript-promises/

Promise is easier than callback because code is readable in promise. Promise has also a method. Methods: then, catch, finally (these methods use callback)
Benefits of Promises
  1. Improves Code Readability
  2. Better handling of asynchronous operations
  3. Better flow of control definition in asynchronous logic
  4. Better Error Handling
A Promise has four states:
    1. fulfilled: Action related to the promise succeeded
    2. rejected: Action related to the promise failed
    3. pending: Promise is still pending i.e not fulfilled or rejected yet
    4. settled: Promise has fulfilled or rejected

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