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What is event bubbling and capturing in JavaScript?

Answer»

Promises in JavaScript are like promises in real life. You promise to do SOMETHING, and then it is done or not done. A promise may be in one of 3 possible states: resolve, rejected, or pending.

They are mainly used to do asynchronous task like calling a REST api and GETTING the result back. So, these network CALLS takes TIME. When the network call is been made, the promise is in Pending state. Once the network call is successful the promise returns a resolve and if it fails it returns resolve.The resolve is CAPTURED by the then() callback function and reject captured by catch() callback function.

Consider the below example. Here inside promiseCleanRoom we generate a random number between 0 and 1. If the number is greater the 0.5, we send a resolve or else we send a reject.
Depending on the case either .then is executed or .catch is executed.

Below is the resolve case


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