1
00:00:01,010 --> 00:00:02,650
‫Finally, let's now handle

2
00:00:02,650 --> 00:00:05,053
‫Mongoose's validation errors.

3
00:00:06,630 --> 00:00:09,750
‫So remember how we tried to update a tour

4
00:00:09,750 --> 00:00:11,410
‫with some invalid data here,

5
00:00:11,410 --> 00:00:13,890
‫and then got this kind of error?

6
00:00:13,890 --> 00:00:15,160
‫Okay.

7
00:00:15,160 --> 00:00:17,923
‫And let's actually try to add another one.

8
00:00:19,890 --> 00:00:24,350
‫So a name that's really short, okay?

9
00:00:24,350 --> 00:00:27,410
‫And because that's not allowed, again.

10
00:00:27,410 --> 00:00:30,680
‫Oh and now we actually no longer can see our error

11
00:00:30,680 --> 00:00:33,000
‫because we're now in production.

12
00:00:33,000 --> 00:00:34,750
‫And of course this error right now

13
00:00:34,750 --> 00:00:36,370
‫is not handled correctly.

14
00:00:36,370 --> 00:00:38,730
‫It is not marked as operational.

15
00:00:38,730 --> 00:00:39,580
‫And so therefore,

16
00:00:39,580 --> 00:00:44,020
‫remember we get this kind of generic error message back.

17
00:00:44,020 --> 00:00:45,040
‫Okay?

18
00:00:45,040 --> 00:00:49,530
‫So just to see the error that we had before,

19
00:00:49,530 --> 00:00:52,263
‫let's quickly switch back to development.

20
00:00:53,810 --> 00:00:55,253
‫So npm start.

21
00:00:58,950 --> 00:01:00,610
‫And,

22
00:01:00,610 --> 00:01:01,810
‫send it now again.

23
00:01:01,810 --> 00:01:05,220
‫And so now we get back our development errors, okay?

24
00:01:05,220 --> 00:01:06,590
‫Because now I want to show you

25
00:01:06,590 --> 00:01:10,410
‫how we can actually create a meaningful error message

26
00:01:10,410 --> 00:01:13,590
‫based on all of this, what we have here.

27
00:01:13,590 --> 00:01:14,670
‫Now right.

28
00:01:14,670 --> 00:01:16,690
‫So inside our error,

29
00:01:16,690 --> 00:01:19,280
‫we get an error properties.

30
00:01:19,280 --> 00:01:21,800
‫And that property itself is an object

31
00:01:21,800 --> 00:01:24,540
‫which has a lot of objects in there,

32
00:01:24,540 --> 00:01:28,770
‫and each of them is for one of the fields that has an error.

33
00:01:28,770 --> 00:01:29,790
‫All right?

34
00:01:29,790 --> 00:01:33,760
‫So the first one here is for the length of the tour.

35
00:01:33,760 --> 00:01:35,760
‫Then the second one is for the difficulty,

36
00:01:35,760 --> 00:01:37,310
‫that is also wrong.

37
00:01:37,310 --> 00:01:40,400
‫And the third one is for the rating, okay?

38
00:01:40,400 --> 00:01:44,520
‫So each of these actually has a nice error message, okay?

39
00:01:44,520 --> 00:01:48,210
‫So basically the one that we defined in our Mongoose schema.

40
00:01:48,210 --> 00:01:50,480
‫And so now we want to extract

41
00:01:50,480 --> 00:01:52,490
‫these three messages from here,

42
00:01:52,490 --> 00:01:55,920
‫and put them all into one string, all right?

43
00:01:55,920 --> 00:01:58,593
‫So let's go ahead and do that.

44
00:01:59,720 --> 00:02:00,553
‫Okay.

45
00:02:00,553 --> 00:02:01,740
‫And again, I'm gonna start

46
00:02:01,740 --> 00:02:05,363
‫by actually creating the conditional down here.

47
00:02:06,720 --> 00:02:07,553
‫So if(error),

48
00:02:09,210 --> 00:02:10,760
‫and actually let's take a look.

49
00:02:12,270 --> 00:02:14,290
‫So here we have the error.

50
00:02:14,290 --> 00:02:16,413
‫We have the errors, all of them.

51
00:02:17,510 --> 00:02:19,840
‫And I need to scroll here.

52
00:02:19,840 --> 00:02:22,320
‫And yeah, so here's the name.

53
00:02:22,320 --> 00:02:26,300
‫So error.name is ValidationError, all right?

54
00:02:26,300 --> 00:02:27,453
‫So let's grab that.

55
00:02:32,150 --> 00:02:32,983
‫Okay.

56
00:02:32,983 --> 00:02:36,010
‫And so this again, is an error created by Mongoose.

57
00:02:36,010 --> 00:02:37,440
‫So just like the first one,

58
00:02:37,440 --> 00:02:40,023
‫and so they look similar, okay.

59
00:02:41,150 --> 00:02:42,553
‫Now I don't want this here.

60
00:02:43,400 --> 00:02:45,410
‫But instead I want that the error

61
00:02:45,410 --> 00:02:48,863
‫should be equal to handleValidationErrorDB,

62
00:02:54,290 --> 00:02:57,123
‫and send in the error, okay?

63
00:02:59,400 --> 00:03:00,933
‫Now let's copy this again.

64
00:03:08,560 --> 00:03:09,840
‫All right.

65
00:03:09,840 --> 00:03:13,723
‫And let's again, simply start by creating our message.

66
00:03:19,090 --> 00:03:20,523
‫Invalid input data.

67
00:03:23,060 --> 00:03:25,043
‫And then let's also return the error.

68
00:03:27,520 --> 00:03:29,020
‫So new AppError(message, 400).

69
00:03:30,275 --> 00:03:31,860
‫So VS Code already recognized

70
00:03:31,860 --> 00:03:35,073
‫that I wanted to type just that, all right?

71
00:03:38,130 --> 00:03:40,280
‫Now in order to create one big string

72
00:03:40,280 --> 00:03:43,400
‫out of all the strings from all the errors,

73
00:03:43,400 --> 00:03:46,330
‫we basically have to loop over all of these objects,

74
00:03:46,330 --> 00:03:51,180
‫and then extract all the error messages into a new array.

75
00:03:51,180 --> 00:03:53,573
‫So let's again, take a look at that.

76
00:03:54,440 --> 00:03:55,320
‫Okay.

77
00:03:55,320 --> 00:03:58,430
‫So the object that has all of the objects

78
00:03:58,430 --> 00:04:01,290
‫in there is errors, okay?

79
00:04:01,290 --> 00:04:03,800
‫So we have one error for name, one for difficulty,

80
00:04:03,800 --> 00:04:05,870
‫and one for ratingsAverage.

81
00:04:05,870 --> 00:04:09,923
‫And so we're gonna basically loop over this errors object.

82
00:04:10,810 --> 00:04:11,660
‫Okay?

83
00:04:11,660 --> 00:04:14,190
‫And in JavaScript, we use Object.values

84
00:04:14,190 --> 00:04:17,290
‫in order to basically loop over an object.

85
00:04:17,290 --> 00:04:19,720
‫So the elements of an object.

86
00:04:19,720 --> 00:04:21,260
‫All right?

87
00:04:21,260 --> 00:04:25,000
‫So let's create a variable here called errors,

88
00:04:25,000 --> 00:04:26,700
‫which again will be an array

89
00:04:26,700 --> 00:04:28,583
‫of all the error messages for now,

90
00:04:29,640 --> 00:04:32,963
‫and now Object.values.

91
00:04:34,930 --> 00:04:38,863
‫And so we want the values of err.errors, all right?

92
00:04:41,540 --> 00:04:44,580
‫And now loop over them using a map.

93
00:04:44,580 --> 00:04:46,160
‫And then in each iteration,

94
00:04:46,160 --> 00:04:50,220
‫we are simply gonna return the error message, okay?

95
00:04:50,220 --> 00:04:54,540
‫So just to make sure we're all on the same page here,

96
00:04:54,540 --> 00:04:59,470
‫the Object.values are these objects, okay?

97
00:04:59,470 --> 00:05:04,190
‫So this object, and this object, and the next one, okay?

98
00:05:04,190 --> 00:05:05,730
‫So these are the values.

99
00:05:05,730 --> 00:05:06,930
‫And so now all we have to do

100
00:05:06,930 --> 00:05:09,110
‫in order to extract the message,

101
00:05:09,110 --> 00:05:12,210
‫is to say value.message, okay?

102
00:05:12,210 --> 00:05:13,533
‫So .message.

103
00:05:16,410 --> 00:05:18,380
‫So basically the current value,

104
00:05:18,380 --> 00:05:19,710
‫or let's say the current element,

105
00:05:19,710 --> 00:05:21,653
‫I like to use element for that,

106
00:05:22,640 --> 00:05:25,423
‫and we want to return el.message.

107
00:05:26,870 --> 00:05:27,703
‫Okay.

108
00:05:28,940 --> 00:05:32,040
‫And now, of course, this should not be here.

109
00:05:32,040 --> 00:05:34,140
‫And you had probably already noticed that.

110
00:05:35,260 --> 00:05:39,930
‫So in fact, this is where we want this, okay?

111
00:05:39,930 --> 00:05:41,280
‫And so now all we need to do

112
00:05:41,280 --> 00:05:45,163
‫is to pluck this into our message string, all right?

113
00:05:46,830 --> 00:05:51,700
‫So errors, and now we simply join all of them together

114
00:05:51,700 --> 00:05:56,700
‫into one string using period and then space, okay?

115
00:05:56,930 --> 00:05:59,263
‫And you will see, in a second, why that is.

116
00:06:00,350 --> 00:06:01,183
‫All right.

117
00:06:02,590 --> 00:06:05,130
‫So let's switch back to production here.

118
00:06:05,130 --> 00:06:07,483
‫So running our production start script.

119
00:06:08,960 --> 00:06:12,083
‫Try it again now and let's wait for it,

120
00:06:13,440 --> 00:06:14,310
‫and bam!

121
00:06:14,310 --> 00:06:15,470
‫Here we go!

122
00:06:15,470 --> 00:06:17,530
‫So invalid input data.

123
00:06:17,530 --> 00:06:19,990
‫Then the first error string,

124
00:06:19,990 --> 00:06:22,150
‫must have more or equal than 10 characters.

125
00:06:22,150 --> 00:06:23,810
‫Then the second one,

126
00:06:23,810 --> 00:06:26,040
‫and the third one.

127
00:06:26,040 --> 00:06:26,900
‫Perfect.

128
00:06:26,900 --> 00:06:30,210
‫And so that's why I used the period and space, okay?

129
00:06:30,210 --> 00:06:33,680
‫So to basically separate these three strings

130
00:06:33,680 --> 00:06:36,210
‫with a period and a space, all right?

131
00:06:36,210 --> 00:06:38,680
‫And now this looks like a very nicely formatted

132
00:06:38,680 --> 00:06:41,693
‫error message that everyone can easily understand.

133
00:06:42,870 --> 00:06:43,703
‫Right?

134
00:06:43,703 --> 00:06:46,180
‫So, we're basically done here.

135
00:06:46,180 --> 00:06:47,013
‫All right.

136
00:06:47,013 --> 00:06:49,890
‫Now we could've made this error, handling error,

137
00:06:49,890 --> 00:06:52,120
‫a lot more complete still.

138
00:06:52,120 --> 00:06:56,640
‫For example, we could define different error severity levels

139
00:06:56,640 --> 00:06:59,130
‫like saying, this error is not so important,

140
00:06:59,130 --> 00:07:01,130
‫this error is medium important,

141
00:07:01,130 --> 00:07:04,770
‫and this error is very important or even critical.

142
00:07:04,770 --> 00:07:08,400
‫And we could also then email some administrator

143
00:07:08,400 --> 00:07:10,430
‫about critical errors.

144
00:07:10,430 --> 00:07:14,120
‫And really, there's a lot of stuff that we could implement.

145
00:07:14,120 --> 00:07:18,300
‫But again, in a kind of small application like this one,

146
00:07:18,300 --> 00:07:21,810
‫what we have here is already really good, okay?

147
00:07:21,810 --> 00:07:24,410
‫So this is quite a robust strategy already

148
00:07:24,410 --> 00:07:25,970
‫that we have implemented here,

149
00:07:25,970 --> 00:07:29,150
‫and I'm really happy with it, okay?

150
00:07:29,150 --> 00:07:32,520
‫So all this logic here with the operational errors

151
00:07:32,520 --> 00:07:34,200
‫that we implemented here,

152
00:07:34,200 --> 00:07:36,393
‫so that's already quite sophisticated.

153
00:07:37,250 --> 00:07:38,083
‫Okay?

154
00:07:39,290 --> 00:07:42,190
‫Now if we were ever to find another error

155
00:07:42,190 --> 00:07:44,420
‫that we want to mark as operational,

156
00:07:44,420 --> 00:07:46,410
‫then of course all we would have to do

157
00:07:46,410 --> 00:07:50,120
‫is something similar to what we have here, okay?

158
00:07:50,120 --> 00:07:53,750
‫So basically implement another function for that one,

159
00:07:53,750 --> 00:07:56,630
‫and then return our own operational error

160
00:07:56,630 --> 00:07:58,620
‫so that the send error production

161
00:07:58,620 --> 00:08:01,580
‫can then actually send that operational error

162
00:08:01,580 --> 00:08:03,473
‫to the client, right?

163
00:08:04,320 --> 00:08:06,580
‫Okay, and with that being said,

164
00:08:06,580 --> 00:08:09,080
‫our error controller is actually finished.

165
00:08:09,080 --> 00:08:12,010
‫But there are still some other errors that we need to handle

166
00:08:12,010 --> 00:08:16,090
‫which are completely outside of Mongo or even of Express.

167
00:08:16,090 --> 00:08:19,123
‫And so we're doing that in the rest of this section.