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Let's now learn about the new operator 2

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with the funny name of nullish coalescing operator. 3

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So in the last video, we used the OR operator 4

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to set a default value 5

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in case that the first value was a falsy value. 6

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So let me bring back that code here, actually. 7

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So this one, 8

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but we're only interested in the OR operator here. 9

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So let's call this one simply guests. 10

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And so let's again remember what happens here, 11

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which is when we set numGuests to zero, 12

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then JavaScript will still take this default value here 13

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and assign it to guests because zero is a falsy value now, 14

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and so therefore, we go to the second operand. 15

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However, fortunately for us, 16

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there is a very good solution to this, 17

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and that's the new operator with the very weird name 18

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of nullish coalescing operator. 19

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It's an operator that was introduced in ES2020, 20

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and it works like this. 21

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So guests, let's call this one Correct now. 22

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And so it works almost the same way as the OR operator, 23

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really almost the same, but it will fix or error here. 24

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So let's see that it does, 25

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and then I'll explain to you why that is. 26

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All right, and now indeed, we get zero. 27

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So we get the real value that is actually here. 28

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And now if we take it off, only then we get 10, 29

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which is the default value that we want. 30

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So why does this work? 31

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Well, it is because the nullish coalescing operator 32

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works with the idea or with the concept 33

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of nullish values instead of falsy values. 34

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And nullish values are null 35

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and undefined. 36

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That's it. 37

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It does not include a zero 38

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or the empty string. 39

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So basically, for the nullish coalescing operator, 40

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it is as if the zero and the empty string 41

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were not falsy values 42

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and were instead truthy values as well. 43

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But again, this operator does work 44

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with the principle of nullish values. 45

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And so all the nullish values 46

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will short circuit the evaluation here. 47

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Okay, so only if this was null or undefined, 48

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only then the second operand here 49

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would be executed and returned. 50

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And so right now, that's the case 51

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as number of guests does not exist, 52

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so we commented it out here. 53

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And so now it is undefined, 54

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and so only then the evaluation continues. 55

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But again, as we put it back, it now is zero, 56

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and zero is not a nullish value. 57

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And therefore, the evaluation here is short circuited, 58

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and immediately, this first non-nullish value is returned. 59

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All right, and that's actually all for now 60

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about this nullish coalescing operator. 61

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It's a really great and really useful operator, 62

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even though right now, it might not seem that useful, 63

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but as we go through the project, 64

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you will see that it really is.