WEBVTT

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In this video you're going to get introduced to modules and file exports so you're gonna use those to

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be able to exchange the variables and functions or methods between different javascript points.

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So I've created a folder file exports inside the node folder so let's move to that folder inside our

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terminal.

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So I'm going to go up one directory so this is where we are.

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And then I'm going to go to file exports.

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All right.

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So now I'm going to create a new file and call it up those deaths and then I'm going to create another

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or a new folder and call it live for library.

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So basically inside our library we're gonna have some JavaScript files with some variables and functions

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which we need inside up daughter day as.

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So first let's get introduced to the module variable

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so if you console the log module let's see what we get by the way you can do this in any javascript

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file.

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So I'm going to run node up most both.

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And here is our module objects.

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So what you are interested in is the exports property which will show you all the variables and functions

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which you exported from other files to this file.

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So at the moment it's empty.

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All right.

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So let's say that we want to use a function greeting

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which is not defined inside this file.

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So is going to be inside a file located in the library.

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So let's create a new file inside the library and call Callie's greeting those checks.

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So inside this file we're going to

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create a function which we will expose to up those days so in this example we're going to export one

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function.

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So what you can do you can access the module objects inside this file and then type exports and said

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that to one function because you want to export only one function.

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So let's say that our function is going to console the log.

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Hello.

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All right

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so now if you go to up those days we need to add another line to say that we're going to be importing

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the function exported from greeting those days and I'm going to call it greeting.

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So the syntax we need to use here is going to be require followed by the location of the file greeting

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vote yes.

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So I'm going to place everything inside quotes.

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So we starting from the current location and then we're going to the library folder and then greeting

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those Jess.

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All right.

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So now let's try this.

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So if you run the node command we can see Hello.

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Meaning that this function is working.

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Let's have a look at our module variable.

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So there are no exports here because we're not exporting anything from uploading.

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But if you run this on greasing lodges and you console that log the module

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variable then this time you will see that we've got something inside the exports.

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You've got a function.

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Perfect.

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Basically we are exporting an anonymous function and that's why you see once if you call this function

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something like greets

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then this will change.

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So let's have a look.

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You can see it's a function and it's called greets.

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All right.

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Perfect.

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So now let's create another example so we're gonna create another file inside the library and we're

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going to call its school those deaths.

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So inside this file we're going to have another objects or function which we will export to up in those

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chairs.

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So this time we're gonna go straight away to the module variable the exports property and we're going

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to add things manually so this is where we are at the moment.

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All right.

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So we're just gonna add for example an average function which will just calculates the average of grades

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which can be found inside an array.

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So we give it an array and then it will calculate the average for us and returns.

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So basically what we need to do we're going to create a variable some which is initiated to 0.

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And then for each element of the array

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we're going to add the value of the variable or the elements to the sum variable like that's quite easy

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okay.

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And then we're going to return the sum divided by the number of grades which which is gonna be the length

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of the array Okay so let's try this.

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Now we exporting this from school not today has to up those days.

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So we need to add another line to up those stairs.

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Right.

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So

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let's call it average

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and again we're gonna use require.

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We're gonna need the location of our file school both days which is gonna be lib.

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School board chance.

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Now the difference between that imbalance is that in that case we are exporting a function from greeting

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those chairs like that's

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and we setting the whole exports property of the module variable to that function.

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Now in this scenario things are slightly different.

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We are just appending average to exports.

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So basically you still need to say that you require that file dots average and this will import the

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average function successfully for it for you.

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So what you can do you can try those console the long average of these grades.

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So for example let's say those we've got

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70 55 90 and 100.

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And let's see what we get

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right.

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So we're getting seventy eight point seventy five.

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So let's try something else.

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So let's try

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eighty nine point one four for example.

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OK just to show you what happens

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OK.

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So now we're getting at this number and let's say that you would like to show only two digits after

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the decimal.

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So you can just add

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two fixed

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and plus two to the method.

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All right.

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So let's try again.

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And here we go

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there.

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That's how you attach a function to the exports property of the module objects.

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Now let's add something else.

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So this time I'm going to add an object grades for example and let's say that it's called a best property

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and an average property.

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OK

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so let's check the module variable and see what we've got

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in the exports.

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You can see that we've got a function and a grades object.

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Right.

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So now let's go to the up votes file and let's access the objects that we have just exported so let's

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log it.

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So again to access it we're going to require the same file and then since we attached grades to the

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exports property then we could just access it like this.

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So let's run

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up more ideas.

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And here we go.

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That's our grades object.

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So hopefully you've got now a good understanding of how to export objects and functions or methods between

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different JavaScript files.

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So in the next video you're gonna start looking at built in modules in new days.

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Now you're going to start with the HP module.