1 00:00:00,150 --> 00:00:06,480 Beautiful, and once we're done setting up aggregation pipeline in Atlas, I want to do the same thing 2 00:00:06,810 --> 00:00:12,730 in our code and in here first, we want to navigate to refugees. 3 00:00:13,170 --> 00:00:16,500 And we're looking for we calculate average rating. 4 00:00:16,770 --> 00:00:17,640 Now, my apologies. 5 00:00:17,640 --> 00:00:24,180 I think I should have went with something more generic because we'll also be looking for number of years, 6 00:00:24,210 --> 00:00:30,420 but hopefully you can forgive me and the way we set everything up is following. 7 00:00:31,200 --> 00:00:33,600 First, I want to go with some kind of value. 8 00:00:33,750 --> 00:00:39,370 In my case, I'm going to call this a result is equal to and this is going to be a synchronous. 9 00:00:39,420 --> 00:00:43,380 So we need to go with a weight when we're looking for our schema. 10 00:00:43,710 --> 00:00:47,130 So we go here with verse and line. 11 00:00:47,400 --> 00:00:49,140 The method name is aggregate. 12 00:00:50,230 --> 00:00:55,360 So syntax is following we go with aggregate, it is a method we invoke. 13 00:00:55,750 --> 00:01:02,890 And just like in our temp, Jess, where essentially we have a our first step, second step. 14 00:01:03,190 --> 00:01:09,700 Sam, we need to do over here where in ways that aggregate, we pass in the right and we'll set up the 15 00:01:09,710 --> 00:01:12,820 steps and you can copy and paste if you want. 16 00:01:12,820 --> 00:01:16,300 In my case, I will set up everything from scratch. 17 00:01:16,690 --> 00:01:22,300 But if you copy and paste, keep in mind that some values you'll have to change here around. 18 00:01:22,780 --> 00:01:24,850 So I'm going to go back here. 19 00:01:24,880 --> 00:01:27,460 I'm going to set up the first step, which is matching. 20 00:01:28,020 --> 00:01:33,340 So go with match and that's the operator, and then I'm going to go with product. 21 00:01:33,520 --> 00:01:34,420 So that's the key. 22 00:01:34,750 --> 00:01:37,000 But in this case, we're not hard coding. 23 00:01:37,480 --> 00:01:40,540 I'm not going to pass in some specific object daddy. 24 00:01:40,870 --> 00:01:46,060 I'll say whatever product the I'm getting in, calculate our trading. 25 00:01:46,450 --> 00:01:47,860 Well, that's the one that I'll use. 26 00:01:48,130 --> 00:01:52,150 Some say product and then I, that's my first stage. 27 00:01:52,570 --> 00:01:56,200 Then we add karma and then where you want to set up another stage. 28 00:01:56,560 --> 00:01:58,290 Now this is the group one, correct? 29 00:01:58,300 --> 00:02:02,710 So we go with group operator and that's the object that we are returning. 30 00:02:03,490 --> 00:02:05,920 And again, I'm going to go with i-D here. 31 00:02:06,430 --> 00:02:11,430 And like Ari previously mentioned, either we go here with product. 32 00:02:12,190 --> 00:02:18,040 So essentially that is just going to get all the reviews in the list that match that product, which 33 00:02:18,040 --> 00:02:19,900 is our list at the end of the day. 34 00:02:20,350 --> 00:02:24,220 So in our example, we can also go with no, that's really up to you. 35 00:02:24,220 --> 00:02:30,280 And I'm not going to repeat the entire set up because I think I already covered up in a previous video 36 00:02:30,460 --> 00:02:37,960 where yes, if you have more complex data, if you have, let's say, some kind of list where you want 37 00:02:37,960 --> 00:02:42,640 to group them by the rating or something like that, then that matters. 38 00:02:42,640 --> 00:02:44,330 Whatever you passing as an idea. 39 00:02:44,350 --> 00:02:45,280 In our case, it doesn't. 40 00:02:45,280 --> 00:02:51,310 Since I want to get the entire list underway and right where we want to go with average rating. 41 00:02:51,340 --> 00:02:53,680 So that's the proper name that I'm getting. 42 00:02:53,890 --> 00:03:01,630 And this one will be equal to an average operator, and I'm going to be looking for my rating. 43 00:03:02,020 --> 00:03:03,070 So rating property. 44 00:03:03,610 --> 00:03:08,240 And also, I want to set up a number of reviews brought in between the videos. 45 00:03:08,260 --> 00:03:10,150 I noticed that there is a tiny bug. 46 00:03:10,510 --> 00:03:13,390 It's not no off line here. 47 00:03:13,390 --> 00:03:14,230 I have no. 48 00:03:15,040 --> 00:03:20,100 So two options, either you change it here or you change it to Nicole and Mike. 49 00:03:20,260 --> 00:03:25,690 I think I'm just going to stick with this one just so I have less things to worry about. 50 00:03:26,020 --> 00:03:27,640 So back in the review. 51 00:03:28,550 --> 00:03:29,750 Let's set up average rating. 52 00:03:29,780 --> 00:03:36,290 That's number one, comma, the number of reviews that is equal to an object, remember some operator 53 00:03:36,590 --> 00:03:38,360 and we showed equal to one. 54 00:03:39,270 --> 00:03:46,350 And what you'll notice once you start deleting, updating or just creating reviews that this value will 55 00:03:46,350 --> 00:03:49,560 be changing, so we go here and we'll go with log. 56 00:03:50,490 --> 00:03:52,800 And I want to see the result. 57 00:03:53,860 --> 00:04:01,480 Right, and we want to go back to the postmen and there, since I'm logged in to Susan, I believe I'm 58 00:04:01,480 --> 00:04:04,510 going to update my review, so let me get all the reviews. 59 00:04:05,790 --> 00:04:13,800 I'll say over here that this is done by and let me take the ad. I mean, the review and then in here, 60 00:04:14,160 --> 00:04:17,130 by the way, I should have went with some different number. 61 00:04:17,490 --> 00:04:23,130 So I go with three and not if we take a look at our code, which you'll notice in the council. 62 00:04:23,130 --> 00:04:23,760 Is this. 63 00:04:23,790 --> 00:04:24,210 All right. 64 00:04:24,990 --> 00:04:31,680 So in the race, since I'm getting all the list items, since I'm grouping all the list items, I have 65 00:04:31,680 --> 00:04:32,640 only one object. 66 00:04:32,910 --> 00:04:40,230 So of course, if you have a more complex grouping, you have multiple objects and you can clearly see 67 00:04:40,230 --> 00:04:41,870 that in Mongo DB docks. 68 00:04:42,300 --> 00:04:44,970 That's why I'm not going to spend any more time on that. 69 00:04:45,330 --> 00:04:49,860 And that in here I have an average rating as well as a number of reviews. 70 00:04:50,070 --> 00:04:51,390 So what's the next step? 71 00:04:51,900 --> 00:04:55,560 Well, the next step is to update the product. 72 00:04:56,470 --> 00:04:58,030 Whose idea is matching this product? 73 00:04:59,110 --> 00:05:06,730 So once I get back my object, I simply want to take these two properties and I want to update of the 74 00:05:06,730 --> 00:05:08,900 product how we can update the product. 75 00:05:08,920 --> 00:05:15,340 Well, we can go with the that model product and then we have access to find one and update. 76 00:05:15,820 --> 00:05:22,660 Now I'm not going to showcase this with post-money yet because I think it's going to take more time. 77 00:05:22,660 --> 00:05:29,740 But we also need to keep in mind that at some point, if we remove all the reviews associated with the 78 00:05:29,740 --> 00:05:32,800 product refresh, Ray will be just empty. 79 00:05:33,640 --> 00:05:34,600 There's going to be nothing there. 80 00:05:34,810 --> 00:05:41,350 Yes, we'll set up the functionality where we update that, but we also need to check whether this object 81 00:05:41,350 --> 00:05:42,520 actually exists. 82 00:05:42,910 --> 00:05:48,430 Therefore, we'll use Chaining Optional Training, which is available in JavaScript, but there's other 83 00:05:48,430 --> 00:05:49,240 methods as well. 84 00:05:49,780 --> 00:05:51,790 So let's go here with a try catch. 85 00:05:51,930 --> 00:05:55,810 First, try catch and in the try block I want to go with. 86 00:05:56,380 --> 00:05:57,220 It is a synchronous. 87 00:05:57,230 --> 00:05:59,020 I'm looking for that model. 88 00:05:59,350 --> 00:06:00,860 And in here, what model do I want? 89 00:06:00,880 --> 00:06:02,350 Well, I want product, correct? 90 00:06:02,350 --> 00:06:10,390 So we'll go here with product when we go find one and update where you know this method. 91 00:06:11,110 --> 00:06:20,200 First thing we pass in is the product ID so we can go here with on the score I.D. and then equals to 92 00:06:20,200 --> 00:06:21,910 a product I.D. Correct? 93 00:06:22,320 --> 00:06:24,160 Then what do we want to update? 94 00:06:24,160 --> 00:06:25,730 Well on a product? 95 00:06:25,750 --> 00:06:27,040 What are the proper names? 96 00:06:27,700 --> 00:06:30,340 Average rating and number of reviews, correct? 97 00:06:30,880 --> 00:06:31,750 Average rating. 98 00:06:32,200 --> 00:06:33,800 And that is equal to what? 99 00:06:33,820 --> 00:06:36,490 Well, now I have my result. 100 00:06:37,000 --> 00:06:37,990 Correct my right. 101 00:06:38,260 --> 00:06:39,670 It's right over here. 102 00:06:40,330 --> 00:06:48,280 But we also need to keep in mind that we'll have to use some kind of math around operation. 103 00:06:48,610 --> 00:06:50,640 So, Mike, I'm just going to go with Matthew. 104 00:06:50,890 --> 00:06:56,860 So same math seal is equal to and nine percent result. 105 00:06:57,680 --> 00:07:00,260 I'm looking for the first item for my object. 106 00:07:00,440 --> 00:07:04,700 But again, there's going to be cases where there are no reviews. 107 00:07:04,790 --> 00:07:08,090 Let's say we remove all the reviews for that one specific product. 108 00:07:08,450 --> 00:07:09,980 Therefore, we'll add here. 109 00:07:10,340 --> 00:07:10,970 Question mark. 110 00:07:11,330 --> 00:07:11,800 And then. 111 00:07:12,290 --> 00:07:14,480 And if you're not familiar, this is optional training. 112 00:07:14,810 --> 00:07:19,850 And if you're interested, I have the video, the entire video or in my YouTube channel decoding at 113 00:07:19,850 --> 00:07:20,030 it. 114 00:07:20,360 --> 00:07:25,730 And more specifically, you're looking for JavaScript Nugget series and there have optional training 115 00:07:25,730 --> 00:07:25,960 one. 116 00:07:26,420 --> 00:07:33,260 And then I'm looking for average rating if it doesn't exist and I simply want to go with zero mike show 117 00:07:33,620 --> 00:07:42,680 and learn what we want to do is copy this and we're looking for not average rating setting number of 118 00:07:42,680 --> 00:07:45,050 years of reviews. 119 00:07:45,470 --> 00:07:47,470 That's the property name on the object again. 120 00:07:47,480 --> 00:07:49,820 We'll go with math that ceiling mount. 121 00:07:49,820 --> 00:07:53,090 In this case, though, Richard don't need to use the math suing. 122 00:07:54,020 --> 00:07:57,380 We'll simply say a result a number of years. 123 00:07:58,100 --> 00:08:01,430 If the property exists, then awesome. 124 00:08:01,790 --> 00:08:07,030 If it doesn't, and we'll just set it equal to A0, we save it. 125 00:08:07,040 --> 00:08:14,780 And now let's test it out where I'm going to go to my post, man, and I'm gonna set it back to one. 126 00:08:15,140 --> 00:08:16,130 Let's send it. 127 00:08:16,490 --> 00:08:21,980 So we're sent back and not sure whether we're still console logging, but we should. 128 00:08:22,100 --> 00:08:25,580 So let me go back here and first in a catch. 129 00:08:25,640 --> 00:08:28,730 Let's just add log and error. 130 00:08:30,300 --> 00:08:35,429 And then above, try and catch, let's log the result, because I want to showcase what is going to 131 00:08:35,429 --> 00:08:40,900 be a result if we are all there viewers and now it's update or I'm sorry. 132 00:08:41,010 --> 00:08:42,270 Now let's check it out. 133 00:08:42,330 --> 00:08:48,660 The get off product and you'll notice that for this product, what's really cool now, average rating 134 00:08:48,660 --> 00:08:50,850 is three because we have five in one. 135 00:08:51,270 --> 00:08:52,830 And what about number of years? 136 00:08:53,280 --> 00:08:54,170 It is one. 137 00:08:54,180 --> 00:09:02,040 So if I log in as John again and I remove all of them, you'll notice some interesting changes where 138 00:09:02,220 --> 00:09:03,690 I'll get all my reviews. 139 00:09:04,090 --> 00:09:05,370 OK, that's a start. 140 00:09:06,160 --> 00:09:10,480 And first, I want to remove John's review, which is five. 141 00:09:10,870 --> 00:09:14,350 I send it, and then again, if I take a look at all the products. 142 00:09:14,740 --> 00:09:15,850 Check it out. 143 00:09:16,240 --> 00:09:17,860 Now I have an average rating one. 144 00:09:18,640 --> 00:09:19,840 That's what we're calculating. 145 00:09:19,840 --> 00:09:20,800 And how many reviews? 146 00:09:21,190 --> 00:09:21,880 Only one. 147 00:09:22,270 --> 00:09:29,380 So if I remove the last one, the Citizens Review notice that everything is going to go back to zero. 148 00:09:29,740 --> 00:09:30,970 So the literature review. 149 00:09:32,160 --> 00:09:39,120 Copy and paste and everything should be back to zero or get all products. 150 00:09:40,500 --> 00:09:45,090 And what do you know, your average rating and number of reviews is zero. 151 00:09:45,470 --> 00:09:49,890 So that's how we can set up the aggregation pipeline in the code. 152 00:09:50,250 --> 00:09:56,400 So if you want, you can utilize some of the code snippets that we got back from Atlas. 153 00:09:56,640 --> 00:09:57,900 That's definitely an option. 154 00:09:58,290 --> 00:10:01,000 But this is essentially how you would Typekit out. 155 00:10:01,020 --> 00:10:04,650 And then lastly, I just want to mention that result is an empty array. 156 00:10:04,980 --> 00:10:11,680 Therefore, we use this option with training where if you will just say, Hey, get me result zero and 157 00:10:11,680 --> 00:10:19,290 then average rating, you get back in error because if is empty, ran JavaScript is going to complain 158 00:10:19,560 --> 00:10:28,320 how I can get the average rating on something that doesn't exist in the array since there is not a first 159 00:10:28,320 --> 00:10:31,170 item in the array, hopefully everything was clear. 160 00:10:31,170 --> 00:10:37,020 I'll remove this console lock for result and now I can move on to setting up our orders.