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You might get a question like this right to function, which helps to achieve multiply A and B and returns

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product of A and B, and as you can see here, we have this strange notation multiply then A and B not

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like two arguments, but this is the first call of the function and this is a second call of the function.

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And actually, if you are getting such question, it means that you are going in the direction of Karen

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and Karen is a special possibility in JavaScript to carry a function.

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And then we can call it like this.

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And actually, here we can implement this stuff with super basic current.

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Let's try this out now.

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So what I want to do, I want to create multiply function.

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And here we're get in our way.

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So it will be number one, for example.

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And here we want to return a function because as you can see here on the top, we're calling on the

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result of monkey to play a b, which means our multiply master return function.

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So here we can write that we are getting F function, which will get B, this is number two, for example.

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And here inside we want to multiply our number one and number two.

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In this case, our second function will deliver fast multiplication of number one and number two.

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And this is how we can use it.

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We can write here console.log.

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We want to call here our multiply function and we are passing a, for example, two.

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And after this were Column B, this is our second function and we're passing inside three.

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Let's look and Rosa am reloading the page and we're getting six, which means this code is working.

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And actually, you can write this multiply function in better way.

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You can simply mid-year returns and then it will be a simple single line.

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So we have here multiply function and we get to number one here.

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Then we want to return a function and we're getting here number two, and we want to multiply our number

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one, multiply number two.

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And this is exactly this same logic, but it is written in the single line.

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I will now command told the previous code.

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And let's check, as you can see, where getting exactly the same result, but this is not really current.

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So if you solve such tasks, typically you will be asked, OK, but what did you write here?

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What does this mean?

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Why we need such strange notation?

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And actually, you must tell that token here regarding current is the next question that you might get

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is create a card of function, and this is actually a difficult question.

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And if you didn't have any experience of current functions, then probably you won't answer it.

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This is why here we a look how we can create the kind of function and why do we need them and actually

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carry functions working exactly like home, multiply here so we can write in browser, for example,

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Kyrie.

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And this is our function.

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We must always pass inside the function that we want to carry.

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In this case, we have, for example, a function with A, B and C.

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So we have three arguments and we want to just some a plus B plus c.

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The main point is that the result of Kyrie is a function, and let's name it carried some.

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So this is how we're using Kyrie.

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What we can do with courage.

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Some later we can weekends right here, our arguments, we have three arguments how we want.

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For example, we can right here one two three.

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Just like three normal arguments, we can also call it was one, two and three, which means we are

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not getting a result until we get getting through arguments.

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So, for example, we have only one argument here one then it will return the partially applied function,

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which means we're getting back a function.

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And then if we will call that function and pass two arguments, then we're getting enough arguments

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and we will return the result.

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And of course, it should be also possible to call the function like this.

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So first of all, Colin, it was one and then were Colin.

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It was two and three.

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And this is how normal the current function is working and we've all created just now.

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So what we want to do here, we want to create the correct function.

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And as I said, this is more advanced stuff and actually it is a good idea to try this function with

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ActionScript five.

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So was function key words just because we were writing something which will be used as a library?

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This is way here.

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I want to write a function.

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And here we are getting the function and actually here on the top, let's write our usage so we understand

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what we are talking about.

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So we said here that we want our car, read some and were Colin here.

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Our carry function and inside were passing the function with A, B and C, and here we want to sum a

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b and C.

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And actually, I can even write it here on the bottom after our car.

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So we can test if it's working.

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So actually, as you can see, here is our carry function and we're getting inside the function.

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This is our f.n.

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So this ABC and A-plus B-plus here is our function here.

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What we want to do now, we want to know how many arguments we have here.

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This is way here.

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I want to create a property which is called Arati.

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And here we can just write function length and we will get them on the arguments here.

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Let's check this out.

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Console.log, Verity.

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And here is our editor.

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I'm looking in the browser and we're getting three because here we have three arguments A, B and C.

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Now we want to return here a function because we know that current function is always a function.

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This is why here let's write function.

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Let's name it.

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For example, f one.

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And here I want to spread our arguments and let's check what we have inside.

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So here console.log F1 and here are our arguments.

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And actually when lot the page.

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As you can see, we don't get anything because we didn't call this card some.

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So what we must do afterwards, we must call this some as a function and we can pass inside something.

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In our case, we can pass two or three.

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This are our three parameters.

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I'm reloading the page and we're getting here f one one two three.

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So we're getting all arguments as an array.

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This is our idea, and obviously we can also call this function just was one.

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Then we will get array was just one argument.

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So what I want to do inside, I want to check how many arguments we've got or if we got enough arguments

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or not.

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This is way here.

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Inside return, we can compare OK, arguments, length.

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This is the length of our array is bigger or equal everything.

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And this means that we are getting enough arguments to come out of the function.

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So here I want to console.log enough arguments.

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In this case, I just want to return here our function and call it with our arguments.

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So I'm spreading our arguments again, and it will just put here all arguments just like they were previously.

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Let's check the SA time to load in the page and we've got a message enough arguments.

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And actually, here we can console.log what we are getting back.

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In this case, we must get our result.

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I'm relied in the page where get in six it is working correctly, which actually means our code already

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works when we are passing inside three arguments at once.

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But it won't work when we are passing less than that.

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This is why we must write here L's condition and inside we can write, for example, console.log need

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more arguments.

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And now after this, we want to return a function.

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As I already said, if we're past, for example, encourage just one argument, it must return a function

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where we can pass additional arguments.

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This is why here we must return a function and we can name it, for example, F2 and inside we will

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pass more.

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Arguments, which actually means this is our first call, this is our second call.

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For example, here one carried some this is also a correct function.

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So let's name it partially correct some and have a call, correct some.

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Now here I want to cancel.

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OK, partially correct some so we can check what it does.

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As you can see here, we inside need arguments.

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And here is our function with more arguments.

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And actually here we want to pass and set some arguments.

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For example, we can pass here two and three, and it will be exactly this.

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More arguments that were rolled here.

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What we want to do now, we want to concatenate our arguments with my arguments to put all our arguments

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inside the color of the function.

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This is where here we can create a variable in your arguments and we want to concatenate our arguments.

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And I am calling second cut and then passing inside more arguments.

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Now here we don't need to call our fan function just like we did here, but we must call our F1 function

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because we want this check for enough arguments again and again, which means we are calling it recursively.

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This is why here I want to return F1 function and I want to spread all our new arguments.

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This is why here three thoughts and your arguments.

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Let's check the real time to load in the page here, where I get in arguments and enough arguments.

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What does it have a mean here?

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Does our current some robust hear one argument we're getting in this house?

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This is our console.log.

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Need more arguments?

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And here's our additional function.

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This is where we're calling this function, and we're passing here our arguments.

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This is this variable.

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Now here we're concatenated our one.

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This is what we passed here.

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And two three and we called our F1.

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So we're getting here again.

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We have enough arguments and Kiev calling our function, and we're getting six.

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Now let's remove all our consulates logs and check how it's working.

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So what I want to try here is our card.

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Some how we can call it, we can call it was one, two and three and we're getting six.

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It is working now.

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We can call it was one.

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As you can see, we're getting back a function and we now can call it with two and three.

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As you can see, we're getting six also, which means it is working and now we can call it here, restore.

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And after this with three and we're getting six, which actually means it is working correctly with

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any amount of arguments and the have recovered some function where we have ten arguments.

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And then here we're doing some operation with stand arguments.

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Then here we will call this function recursively until we get all needed arguments, as you can see

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right and carry function is not that easy.

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And if you never did it before, it is difficult to write this directly in the interview, especially

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just on the piece of paper and the last question that you might get here.

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Okay, but why do we need carry function and what your correct function can do?

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This is why he he'll want now to use our country function on our rail project and what we can do here,

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we can carry two functions get and map.

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Let's try this out.

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I want to create a get function and they want to carry it.

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This is why I am calling this car function and inside am passing the function with two properties.

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First of all, it will be property.

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And secondly, it will be an object.

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And what we want to return here.

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We just want to take an object by a key and it will be property.

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Let's check how it works.

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As you can see here, we have our get.

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And here we are passing to arguments.

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First of all, property, for example.

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And secondly, our object, for example, +1.

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In this case, we getting one back.

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What we can do here, we can now because it's carried.

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Just call it was one argument.

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Just proceed.

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And as you can see, we getting back a current function.

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Now we can store it somewhere and reuse.

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For example, we can create here additional function.

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Get it.

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And we're calling here, get with just property ID.

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And now, as you can see in browser, we can use get a D function everywhere across our application

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on any object to get a property ID from it.

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Now we can do exactly the same with map, for example, here.

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I want to create map and they want to carry a map function.

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So here we're getting a function, which is an argument of the map and values, which is in the.

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And here I want just to call a plain JavaScript values that map and then pass in our function inside.

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But now our map is carried, which means we can use it everywhere, like a road map.

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For example, we can pass inside our map get ID.

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And now here is a second argument we can pass an array and just have here.

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ID equals one.

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As you can see here, with those actually got an array of IDs with the help of the map and actually

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help us to arguments, but we can also carry it.

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For example, we can name a function here const get IDs.

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And here we want to call our map on Get ID.

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In this case, we have a partial applied function, get ideas and we can use it to get ideas from any

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array.

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For example, here where I write and get IDs and where Colin disfunction on the array was object inside

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and we have here a D1.

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And as you can see, it is working and this is exactly the need of the current to write JavaScript and

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functional way.

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And yet this is quite advanced topic.

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This is why it is completely fine if you don't know this topic as a beginner, but at least you must

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have some basic understanding of what is current and why do you need to tone?