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Now it's time to practice everything 2

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that you just learned about ES6 classes, 3

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and so let's now do coding challenge number two, 4

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and the goal of this one 5

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is to basically recreate challenge number one, 6

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but this time using an ES6 class, 7

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then besides that, 8

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I also want you to add a getter, 9

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which should be called speedUS, 10

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and this one should return the current speed 11

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in miles per hour. 12

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So remember that the original speed 13

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is in kilometers per hour, 14

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and people in the US are usually not used to that, 15

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and so we can create a special getter called speedUS, 16

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and to do the conversion from kilometers per hour 17

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to miles per hour, all you need to do is to divide by 1.6, 18

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then you should also implement a setter 19

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with the same name of speedUS 20

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so that people can basically set the speed 21

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also in miles per hour, 22

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but of course, that value should then be stored in the class 23

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as kilometers per hour, 24

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and so before storing the value, 25

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you need to multiply it by 1.6, 26

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so to convert it back to kilometers per hour, 27

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and then take this test data, number one here, 28

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and create a new car and experiment 29

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with all of the methods and getters and setters. 30

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So have some fun with this one, 31

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and I'll see you back here once you are ready. 32

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Okay. 33

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So hopefully you did that without any problems 34

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and you don't even need my solution, 35

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but of course, as always, 36

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I will still show it to you, 37

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and what I'm gonna do is to simply copy the code 38

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that we wrote earlier, 39

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and I will then convert it to a class 40

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because that's actually not that hard. 41

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So here, we just need to call it a class 42

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and let me call it cl again for class, 43

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and okay. 44

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So then the curly braces, 45

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so one in the beginning, one in the end, 46

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then this function is actually called the constructor, 47

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and the rest is the same. 48

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Here we don't need these, don't need these, 49

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and here we don't need the prototype, 50

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so that's the whole point of using classes, 51

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and then we don't need this function, 52

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and besides that, that's actually it. 53

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So that's the constructor function 54

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plus the methods that we added to its prototype property 55

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simply converted to a class. 56

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And all right, so that was pretty easy. 57

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Now let's talk about the speedUS getter and setter. 58

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So first up the getter, which is easier. 59

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So speedUS and this one does not need any input 60

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and it will simply return this.speed 61

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and then divide it by 1.6, 62

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as I instructed up there in the text. 63

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Alright, and let's already test this now, 64

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and the test data here is Ford 65

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going at 120 kilometers per hour. 66

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So that's a new CarCl 67

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with the make of Ford 68

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and a speed of 120. 69

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So let's accelerate here a little bit, 70

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but before we do that, 71

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let's actually also read the speed in the US, 72

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because I actually know that 120 is 75 miles per hour, 73

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and so then I can know if this actually worked, 74

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and this one here is simply returns the value, 75

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and so we need to log it to the console. 76

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And all right, 77

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so indeed this 75 here coming from line 270 78

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is this speedUS property, 79

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So again, we basically transformed a method here 80

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into a property 81

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so that we read like this by using a getter, 82

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then we accelerate a little bit, so we increase to 130, 83

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and so that means that these methods, they keep working, 84

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and so our conversion to a class a works flawlessly. 85

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And now to finish, 86

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let's just implement the setter here as well. 87

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So set speedUS, 88

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and then remember we always need 89

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to take exactly one argument, 90

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so that's gonna be the speed, of course, 91

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and so here, we want to set the speed, 92

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but of course, in kilometers per hour, 93

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and so we take the speed and multiply it by 1.6, 94

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and so now if we do ford.speed 95

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equals 50 miles per hour, 96

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then let's take a look at the ford object, 97

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and here of course, it needs to be US. 98

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All right, and so here we set the speed to 50, 99

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and then what we get here is 80, 100

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and so 80 is indeed 50 times 1.6. 101

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And so I think that's actually it. 102

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And yeah. 103

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So challenge number two completed.