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After the very important map, filter 2

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and reduce methods, 3

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we still have some more methods to learn 4

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which are also super important and used all the time. 5

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So in this lecture, 6

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we're gonna talk about the Find method. 7

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So as the name says, 8

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we can use the Find method to retrieve one element 9

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of an array based on a condition. 10

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So let's again, use all movements, 11

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and so find and just like the other methods 12

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that we've been talking about, 13

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the Find method also accepts a condition. 14

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And just like the other array methods we've been talking 15

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about the find method also accepts a callback function 16

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which will then be called as the method loops 17

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over the array, all right? 18

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So Find is basically just another method 19

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that loops over the array 20

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but then it does something different. 21

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And in this case 22

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what the Find method does is 23

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to retrieve an element of the array. 24

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So as always the current element of the iteration 25

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is the movement and then here we specify a condition. 26

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So let's say movement less than zero, 27

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so basically this is here, a withdrawal, right? 28

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So a negative movement. 29

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So you see that just like the Filter method, 30

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the Find method also needs a callback function 31

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that returns a Boolean. 32

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So the result of this is of course, 33

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is either true or false. 34

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Now, unlike the Filter method, 35

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the Find method will actually not return a new array 36

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but it will only return the first element 37

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in the array that satisfies this condition. 38

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So basically in other words, 39

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the first element in the array for which 40

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this operation here becomes true. 41

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And so basically this here will return to first withdrawal. 42

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So first withdrawal 43

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is this. 44

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So lets log the movements again to the console 45

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and then let's also log the first withdrawal. 46

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And so indeed -400 here is 47

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the very first value 48

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that appears in the array that is negative, 49

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okay? 50

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So as you see, the Find method is a bit similar 51

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to the Filter method, 52

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but there are two fundamental differences. 53

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First Filter returns all the elements 54

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that match the condition while the Find method 55

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only returns the first one and second 56

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and even more important, the Filter method returns 57

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a new array while Find only returns the element itself 58

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and not an array, okay? 59

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So make sure that you understand 60

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this fundamental difference. 61

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Now this example here is not really exciting, 62

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and so let's now take it to the next level 63

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and start actually working with our array of objects. 64

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So that's this accounts, array, remember, 65

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so this array, which contains the four objects where each 66

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of them is one account. 67

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And as I mentioned earlier, 68

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this is a pretty common data structure in JavaScript, 69

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and so let's now work with this together 70

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with the Find method, 71

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because in this context, 72

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the Find method actually becomes really useful. 73

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So that's because using Find, 74

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we cannot basically find an object 75

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in the array based on some property of that object, 76

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and so that's really cool. 77

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So let me show it to you. 78

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So let's create a variable called Account 79

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and it's gonna be accounts. 80

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So all the accounts.find and then, or callback, 81

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and so as we loop over accounts 82

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each of the current elements is one account, 83

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okay? 84

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And so now let's say we want to select one 85

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of the accounts by the name. 86

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Now, this disappeared here so let's bring it back, 87

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okay? 88

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So let's say we want to get the account 89

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where the owner is Jessica Davis, right? 90

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So we can simply do account.owner=Jessica Davis. 91

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So let's see, 92

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just the account, 93

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and indeed we get now only this object 94

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and this is really, really powerful of a race and objects. 95

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So where one array contains multiple objects 96

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which all have a similar structure. 97

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So all of them here have an owner 98

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have a movement, a pin, a username, and so on and so forth. 99

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So using the Find method, we can 100

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then search this array basically 101

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to find an object that matches 102

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a certain property that we already know. 103

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So in this case, that property that we know 104

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is the name, all right? 105

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And so we simply compare Jessica Davis here 106

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with the account owner. 107

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And whenever this condition here is true, 108

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well, then that object is returned. 109

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So usually the goal of the Find method 110

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is to just find exactly one element, 111

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and therefore we usually set up a condition 112

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where only one element can satisfy that condition. 113

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And so that's why we used the equal operator here, okay? 114

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So if the owner names are unique 115

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then this equal operator here 116

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will only ever match one account with this name here. 117

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All right, and we will actually use this in the next couple 118

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of lectures to implement the login feature, 119

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and also some other features. 120

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Now, I'm gonna leave it to you here 121

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as a challenge to implement this functionality using 122

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the for off loop, just like we have been doing it 123

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with some of the other methods, like map and filter. 124

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So we have also been implementing 125

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these using the for off loop just to see the difference. 126

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But now I'm not gonna do that 127

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but I'm leaving it here as an idea for you to do that. 128

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Now anyway, let's go now to the next video 129

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and actually start to implement the login functionality.