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In the last section we continued developing this analogy to better understand how redux works internally

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in this video.

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I want to get a better understanding of what is going on with this form right here.

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Remember we had said that a customer is going to fill out a form handed off to the former receiver.

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The pharmacy will make a copy of it and then hand it off to each department.

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Along with that department's little slice of data.

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All right.

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So we're going to imagine that every form that gets filled out by a customer is going to have two different

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parts.

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It's going to be essentially a sheet of paper with some fields at the top that the customer has to write

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in and then a field at the bottom that has more information that the customer has to enter.

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So we'll say that every form has a type assigned to it.

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The type of the form essentially declares what the purpose of the form is.

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Remember our insurance company has two broad objects that a customer is going to use to interact with

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it.

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A customer can create a policy and a customer can also create a claim.

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So chances are that we would want to have different forms for creating a policy and for creating a claim

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as well.

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So we'll do it we'll declare it the purpose of each form as a type.

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At the very top of each form and then inside the body of the form which we might refer to as the payload

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We'll have the customer write down some information relevant to them and what they're trying to do.

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So in the case that a customer is trying to create a claim and get some money from the insurance company

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we might want the customer to give us their name so that we can identify them.

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And we also might want the customer to tell us how much money they think that they should be paid which

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you might refer to as say our claim amount now in total.

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I think that our company would need three different types of forms.

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We would need a form for a customer to create a policy.

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We would need a form for them to create a claim and then chances are that eventually a customer would

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not want to be a member of our insurance company anymore.

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And so they might submit a another form to delete their active policy.

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So in total three types type 1 Type 2 type 3 and each different type of form it's going to have a different

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set of information inside its payload.

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In one case to create a policy the customer might need to provide their name along with some initial

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money that they are going to pay to us when they want to create a claim they are going to give us their

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name and tell us how much money they want to get.

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And then when they want to delete a policy chances are they just need to tell us their name so that

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we can go into our big list of people who have policies and just remove them from that list.

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OK.

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So we have a better idea of forms and departments and this entire flow.

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Well it sounds very quickly walked through the process of how each of these different departments would

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process each of those different form types.

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So in this step right here in the next couple of diagrams things are going to get a little bit more

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detailed.

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But remember we're going to eventually write out some code to model this entire insurance company.

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And so it is important that you understand what is going on internally inside of each of these departments

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so that we can actually write some code to model this stuff.

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OK.

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So let's imagine that our 4 receiver gets a form from a customer and this the purpose of this form is

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possibly to create a new claim for receivers are going to take that form and hand it off to the claims

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history department whose job is to record a list of all the different claims that have ever been created

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when the form receiver hands off that form.

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They're also going to get the claims history department.

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That list of all the different claims that have been created previously because remember the idea here

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now is that we want to have all of our data be centralized inside of this outside data store and only

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when a department is given a form are they going to be given their little data set right here and then

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it would be up to the claims history department to update that little list of claims history and then

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afterwards go and update the claims history list inside of our entire company data so internally the

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claims history department is going to take a list of all previous claims in the form and then they're

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going to look at the form and they're going to say OK is the form that is coming in trying to create

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a claim.

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Remember we had said that every department was going to receive a copy of every form.

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So that claims history department needs to look at the form type and decide whether or not the form

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is trying to create a claim if it's not trying to create a claim.

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Chances are this department doesn't care about it they don't care about policies they just care about

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claims.

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So if this form is not trying to create a claim no then it claims history department is going to say

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I don't care.

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Just take that list of claims that you just gave us and we're going to return that.

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And so we returned the unchanged list of claims and we can kind of imagine that that would be the step

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where the list of claims comes out the other end and goes back to our original company repository of

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all data now on the other hand if the form that is coming in is trying to create a claim yes then the

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claims history department is going to say OK I need to understand who is trying to create this claim.

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So it's going to pull off the payload part of that form.

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It's going to add that to the list of claims and then it's going to essentially take that list of claims

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and dump it out front in order to make sure that it updates the central repository of claims history

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data.

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All right.

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Now let's go through the same process with the accounting department as well.

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So with the accounting department we would have our former Sievert say Hey yeah.

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So it just dropped off a form right here.

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So here is the form.

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And by the way here's also our bag with all of our company money inside of it.

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So remember this would in theory be the company money that is stored inside of our central repository

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right here.

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So the accounting department gets the form along with a bag of all of our company's money.

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So then that the accounting department is going to look at that form and they're going to see if the

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form is a claim.

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If it's a claim then the accounting department is going to pull the payload part off that form they're

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going to see how much money the company wants or some of the customer wants as part of the claim.

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And let's imagine that the customer is saying that they just got into an accident and they claim that

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they need $20.

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So the accounting department is going to take that $20 out of the bag and send it off to the customer.

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And then after that the accounting department will take the rest of the money in the bag which is now

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down to 80 because they just took out 20 and they'll return it from their department so that it can

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go back to that central repository.

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Now that's not the only type of form that the accounting department probably cares about the accounting

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department probably also cares about the case in which someone is trying to sign up for a new policy.

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So the accounting department is also going to look for forms of type create policy.

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If they get one then remember the create policy form is going to contain some amount of money to initially

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sign up for a policy.

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So we're going to imagine maybe they include $20 to sign up for a new policy here.

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So the accounting department is going to take that money and put it into our big bag of money and return

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that.

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And now our company balance is now at 120 and then in the final case I don't hear if the person or the

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form is not trying to create a claim and not trying to create a policy then they can Department is going

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to say I don't care just to turn our bag of money with the original hundred dollars and they're going

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to throw it out the other side.

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All right so just one more step.

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So this is the final foreign type or the final department the policies Department.

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So again we're going to imagine the Ford receiver takes the form that was just handed to them by a customer.

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They're going to hand it to our policies Department along with our list of everyone who holds a policy.

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So the policies Department is going to look at that form.

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They're going to look at that type on it.

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They're going to say OK is this form the type that is trying to create a policy or end a policy if it's

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not then they're going to say oh I don't care about this form and they're going to dump out the original

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list of people who have a policy completely unchanged.

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But if the form is trying to create a policy or end up policy then they're going to say all right are

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they trying to end a policy then I'm going to find their name and take it off that list.

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Otherwise if they're trying to create a policy then they're going to take the name off the form and

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add it to the list and after they produce this new list over here that says everyone who has a policy

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just as before are going to say that that new list of people who have policies is going to go back to

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this central repository up here.

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All right.

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So I know that was an incredible amount of detail but that is it for the analogy.

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So I think you now understand the entire flow of what is going on inside of our insurance company.

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Remember in total we've got the customer who drops off the form.

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The form has a type and a payload.

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The form receiver going to make a copy that form handed off to each different department along with

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each different departments little slice of company data.

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Each department is going to look at the foreign type and decide whether or not it has to process the

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form.

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If they do they're going to make an update to their little slice of data and then eventually return

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it out the other end and send it back to this central company repository.

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So now that you understand this kind of analogy here we're going to take another quick pause come back

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the next section.

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I'm going to tell you exactly how this all relates precisely to the world of redux.

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All right.

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So quick break and I'll see you in just a minute.