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In this video.

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Let's talk about promise.

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Well, promise is also another way of writing async code.

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In the previous video, we use callback to write async code.

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So in this particular video, let's see how we can also use promise to write a same code.

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But before we continue on, let's have clear definition or clear meaning of a promise.

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So in a layman's understanding of a promise, let's say that if you promise someone, there are three

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things that comes out well.

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So let's say that I promise you I'm going to create a course on ecommerce.

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That is my promise.

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So before promising, there are three states that goes into play.

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One is about word thinking about the promise, and then after thinking it can happen that I can fulfill

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my promise or three, I can fulfill my promise.

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Well, let's take this in programming context.

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Let's say that we want to watch YouTube videos.

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So as soon as we enter the title of the video, we want to watch and hit enter.

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Let's see what involve one.

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We have what is called pending.

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That is why you will see loading on your screen, meaning that your promise is now in pending state

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and step two is as soon as we see the video that we are requesting, it means that your promise has

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been fulfilled.

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But let's say that due to some error, let's say network error, we see that we have Bush couldn't find

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or network error or couldn't find.

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In that case, your promise is what failed.

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You could see in real life we have these three states and then in programming we have three states as

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well.

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So that's our whole promise is all about.

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So technically a promise represents an object that may produce a value sometime in the future.

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And the value is what we talk about in three states, right.

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Pending for or success.

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So let's move step by step.

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Well, the values of the states can be one independent state, as we discussed.

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And two is a camp for field or success.

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And lastly, your promise can fail.

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So that is the basic understanding of a promise.

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So any time you make use of promise, it means that we are getting these three states that is coming

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out when you make use of promise.

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Well, so instead of using callback promises comes into play to make our life easier.

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With promise, you're going to have clean code so that we can implement all these logic in our code.

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Better still, for callback we can, but looking at syntax promise will be much easier to read than

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callback.

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So the next video.

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Let's see how we can create our first promise.