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In this video.

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Let's see how we can verify this generated token.

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So back to the file.

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This is what we are going to do.

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We are going to create a function to verify the token.

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So this is the function to generate token.

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The next function is going to be point number two.

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Here is going to be verify token.

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And the function goes like this.

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Token is equal to this function.

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We take in the token that we want to verify.

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So inside here we are going to make this of the package called JWT above here.

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The one that we have required.

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All right.

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And on that, we have a method called verify and this verify fixing three argument because we are dealing

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with callback here.

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We can use async await, but let's make it pretty simple here by using callback here.

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So you pass in the token that you're passing to this function.

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And then the key that was used to sign the token and the key was this one.

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The one that we use here is the key.

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The second element.

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And then third element is going to be the callback.

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And for this callback we have access to error and then the decoded user as that and then inside the

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function body, we will have access to the user.

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So let's check if there is error.

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It means that there is something wrong with the token.

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So we can quickly return from this function.

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Let's return object with some properties like this.

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We can see stateless, meaning the status of the verification is false or failed.

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Right.

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And then we can provide a message by saying invalid.

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Tolkien.

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Or token expired.

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You can give it a neat descriptive name.

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So otherwise.

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After Eve, it means that everything went on well.

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And then we can go ahead and then return the decoded user.

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All right, so here we go.

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We can return it here.

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Has decoded.

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Perfect.

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So let's go ahead and then run this function called verify and you pass in the token.

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So this what we are going to do.

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Back to the to call the token here.

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This is a function that we are trying to implement.

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Where is going to take the token and then verify.

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And that's what this function is doing over here.

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So let's see.

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Let's go ahead to the root for logging in and then let's copy this token.

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So let's get back to the two and let's see how we can verify this one here.

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If I paste it, you can see that I got back the entire user for signing in and that is it.

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And you can see that we have what is called Issue Act and Expiration Act and this is what we are going

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to get inside our code.

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So let me copy that and back to the file and let me paste here as an argument or I can assign to a variable.

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Let me paste it inside here as the argument.

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So let's save it.

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And to be able to see the decoded user less console.log from this function as decoded.

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When I save the file, let's check the terminal and you can see that we have the user, which is same

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as the one we saw when we use the tool from JWT.

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Let's look at the database here.

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We have the user.

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This user represents the user we use to sign meaning to generate this token and we got it back and we

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have two properties ie 80 which simply means issue add and this is the date that it was issued and the

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expiration ad as this one and they are in milliseconds.

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So this is how we verify a token.

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So what we are going to do is that after a token has been generated, then we are going to create a

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murderer always to check the request that is coming in.

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If a user passes this token in that way, we are going to take that token and then verify it.

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So this is how we verify a token in this video.

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Let's continue from here and see how we can continue to implement authentication system using this approach.