WEBVTT 00:00.480 --> 00:10.800 Hey everyone, in this video I will show you how we can do the bisimulation for the post. 00:11.040 --> 00:14.640 Okay, I want to do it similar with the five books. 00:14.880 --> 00:19.200 Our review infinite scroll right in the front end. 00:19.240 --> 00:24.640 I will show you how we can integrate us right now let's focus in the API part. 00:25.280 --> 00:29.840 So how do we do that? 00:31.240 --> 00:41.320 Well, if you know Azure you already know, uh, something like language and vice versa right. 00:41.320 --> 00:44.120 Like that okay. 00:44.120 --> 00:47.680 It will do some visualization using this way. 00:48.760 --> 00:55.680 But it's not good for those application right now okay. 00:58.440 --> 01:04.070 If you remember in MongoDB we have some method to do the skip. 01:05.790 --> 01:11.990 Let me say right here we have something called skip. 01:12.270 --> 01:12.830 Okay. 01:13.070 --> 01:24.910 And we have a limit also with this approach it very bad performance when we use the skip over here okay. 01:25.150 --> 01:29.830 And it not good for infinite scroll. 01:30.350 --> 01:32.590 So for that reason we need to another way. 01:34.070 --> 01:34.550 Okay. 01:34.590 --> 01:37.790 Right now let me show you how we can do that. 01:38.630 --> 01:40.150 I want to do similar. 01:40.630 --> 01:42.590 First of all right here we have a limit. 01:43.030 --> 01:43.550 Okay. 01:43.750 --> 01:45.430 Maybe I remove the limit one. 01:46.030 --> 01:57.670 And when I find that I will start from decrement with the created add. 01:59.380 --> 01:59.900 okay. 02:01.020 --> 02:01.620 Possible. 02:01.660 --> 02:04.900 Right here and right here. 02:06.140 --> 02:06.860 Let me say. 02:10.180 --> 02:10.740 Okay. 02:10.740 --> 02:14.500 This here will be the new one. 02:14.540 --> 02:14.820 Okay. 02:14.860 --> 02:16.860 So for that reason, we need to shortly. 02:16.860 --> 02:18.940 But first let me show you. 02:18.980 --> 02:20.300 Firstly I will show. 02:28.860 --> 02:32.380 Up with a minus one. 02:37.260 --> 02:39.460 Uh, actually I will. 02:42.620 --> 02:43.620 So let us. 02:46.620 --> 02:47.180 Okay. 02:47.740 --> 02:48.500 Let me say. 02:56.010 --> 02:58.370 This year will be the new one. 02:58.410 --> 03:00.050 It later I will add the limit. 03:00.050 --> 03:10.690 For example, I limit one okay I will, it will take one recourse and I will take a look at the created 03:10.730 --> 03:11.450 order here. 03:11.930 --> 03:17.130 I will copy that and I will put that inside the cursor cursor. 03:20.210 --> 03:21.210 With something like this. 03:21.650 --> 03:33.210 And I will say after I say I will file with the less than operator to file the another object. 03:33.250 --> 03:33.770 Okay. 03:34.210 --> 03:36.250 Right now it is not clear. 03:36.730 --> 03:42.090 I will show you it got and I will explain okay. 03:42.210 --> 03:44.290 Don't worry if you don't understand right now. 03:44.290 --> 03:46.170 Firstly we need the source right? 03:46.730 --> 03:48.610 And we need the limits also. 03:51.810 --> 03:52.370 And. 03:55.560 --> 03:55.880 Um. 04:00.560 --> 04:01.600 We will screen. 04:03.800 --> 04:07.080 Memory limits will be ten bucks. 04:08.320 --> 04:08.840 Okay. 04:09.120 --> 04:12.160 And I will fix the controller a little bit inside the box. 04:12.160 --> 04:14.000 Controller over here. 04:16.240 --> 04:17.080 Inside. 04:17.080 --> 04:19.000 Get get all. 04:19.600 --> 04:22.720 We need to vote with the query. 04:24.680 --> 04:25.240 Okay. 04:25.560 --> 04:26.640 We will request. 04:28.840 --> 04:30.480 And request right here. 04:31.840 --> 04:39.560 We raise the bar and make sure this is the number we can pass into the pie. 04:42.680 --> 04:43.200 Okay. 04:43.920 --> 04:45.600 We need to move the limits over here. 04:46.000 --> 04:48.320 And one more thing will be the cursor. 04:49.240 --> 04:49.800 Cursor. 04:52.080 --> 04:53.340 I will remove Here. 04:57.860 --> 04:58.460 We go. 05:07.780 --> 05:11.060 I knew that if I won, let me go solo for you. 05:11.100 --> 05:12.420 What is the limit? 05:17.020 --> 05:17.540 Limit? 05:18.180 --> 05:18.620 And. 05:27.580 --> 05:30.500 From here, if I send with this information. 05:30.820 --> 05:32.380 Okay, this is the query. 05:32.580 --> 05:33.060 Okay. 05:33.980 --> 05:37.340 Let's say right here, you can say we have a limit. 05:37.340 --> 05:43.620 And right by this information I will show you we have a source. 05:43.660 --> 05:45.620 We have a limit. 05:48.020 --> 05:51.730 Right now I will limit with the limit right here. 05:52.850 --> 05:54.530 And I will block one. 05:55.210 --> 05:58.490 And I will show you why we need the plus one right here. 05:58.890 --> 05:59.490 Don't worry. 06:01.250 --> 06:02.050 After that. 06:05.490 --> 06:07.210 We need the cross value. 06:07.850 --> 06:15.250 So now we have a hash list by a not okay with this thing I will drag a box. 06:15.890 --> 06:16.810 Not length. 06:17.730 --> 06:21.490 Right run limit between. 06:21.530 --> 06:24.770 Right here we have list by right. 06:25.530 --> 06:27.050 And I will create an item. 06:28.890 --> 06:31.850 The item we will have box. 06:39.090 --> 06:40.330 We have set by. 06:41.250 --> 06:48.410 If we have a hardness by we will use a box not slide we will remove. 06:52.000 --> 06:53.720 The one from here. 06:54.960 --> 06:58.080 And if not, we need to get the boss over here. 06:58.120 --> 07:05.120 Okay, we already have a fast paced and agile, and in here we need to move a little bit. 07:05.160 --> 07:05.960 One more thing. 07:06.520 --> 07:08.640 We need to check if the cursor. 07:09.320 --> 07:12.520 Is it okay, because, uh. 07:12.760 --> 07:13.400 Is it? 07:14.080 --> 07:17.920 We need to create a victory for us. 07:22.760 --> 07:25.480 Where are we going to object? 07:30.600 --> 07:38.080 I will put a little bit of script over here where we not created equal. 07:41.280 --> 07:46.800 Let's not put a new line and move the cursor over here. 07:49.270 --> 07:49.790 Okay. 07:50.550 --> 07:58.270 And with the file method I will move that to. 08:00.790 --> 08:04.270 I will move that over here right away. 08:14.470 --> 08:19.230 And right now let me explain for you what actually happened right now. 08:20.110 --> 08:23.150 Firstly not all this line. 08:23.190 --> 08:26.030 Let me explain for you why we need two plus one. 08:26.350 --> 08:31.670 We need two plus one because we want to check it has next bye or not. 08:31.710 --> 08:32.230 Right. 08:32.590 --> 08:35.870 For example, in here the boss right here is a limit. 08:35.870 --> 08:38.550 Plus one possible limit will be ten. 08:38.790 --> 08:39.270 Okay. 08:39.790 --> 08:43.990 Ten plus one will be 11 and 11. 08:44.030 --> 08:52.540 Also greater than Then Roy followed by Ruby become Joe and we call it Joe. 08:52.860 --> 08:59.900 So for reasons we will extract from 1111 into the ten element, okay. 09:00.020 --> 09:10.260 It means this line here it will be somehow got the one last element from the boss below here. 09:10.300 --> 09:13.420 Because over here we start 11 element right. 09:13.660 --> 09:15.260 So what is this guy? 09:15.780 --> 09:18.180 We need to remove the last one. 09:19.420 --> 09:19.940 Okay. 09:20.660 --> 09:23.180 That is with this ten. 09:23.220 --> 09:24.420 We can check it out. 09:24.460 --> 09:26.100 Let's buy another an item. 09:26.580 --> 09:29.300 And what is the final method right here. 09:30.500 --> 09:31.820 Well, let me show you. 09:34.300 --> 09:35.060 First one. 09:36.580 --> 09:39.380 Um, certainly. 09:39.940 --> 09:41.020 For example. 09:44.100 --> 09:53.610 If we put the cursor right here, it means we want to do some visualization, right? 09:53.650 --> 09:58.450 We want to pagination between right here we have a cursor. 09:58.970 --> 10:04.650 And we will create a query for that cursor using the less than operator. 10:04.930 --> 10:05.250 Okay. 10:05.290 --> 10:08.730 First of all right now is uh. 10:14.290 --> 10:14.730 Here. 10:17.130 --> 10:17.570 Okay. 10:17.770 --> 10:20.290 First of all this is the some days okay. 10:20.330 --> 10:24.930 For example, this is the some timestamp or some days right here. 10:25.410 --> 10:33.770 Firstly we will show we will show by from top to bottom something like this. 10:33.770 --> 10:34.210 Right. 10:36.210 --> 10:39.250 With this field it will start something like that. 10:39.850 --> 10:42.330 And first of all with the limit will be one. 10:42.890 --> 10:45.600 First of all, we would limit we reward whatever. 10:46.080 --> 10:51.560 If the limit will be one, it will only return that this line. 10:51.600 --> 10:52.040 Okay. 10:52.320 --> 10:55.520 And we remove this line to the closure to very less. 10:55.520 --> 11:03.400 Let me show you what exactly that right now I remove the limit will be one because right here we only 11:03.400 --> 11:05.600 have two document. 11:07.080 --> 11:07.640 Okay. 11:08.720 --> 11:14.320 Right here I will say, uh, if we don't put anything, let's say. 11:17.080 --> 11:18.280 Validation fail. 11:23.880 --> 11:25.560 Or the reason? 11:25.560 --> 11:28.960 Because right here it is. 11:29.280 --> 11:34.120 Uh, empty string right here. 11:34.120 --> 11:40.520 We need to put over here and let me remove. 11:41.080 --> 11:41.950 We don't need that. 11:42.110 --> 11:42.510 So. 11:47.990 --> 11:49.750 Let me show you what exactly? 11:49.750 --> 11:50.150 That. 12:03.830 --> 12:08.590 Uh, but before that, let me use that. 12:09.430 --> 12:11.830 Instead of using the box, I will using the icon. 12:13.030 --> 12:13.550 Okay. 12:14.390 --> 12:21.510 And, uh, instead of return here, I will return the box with the K. 12:25.070 --> 12:26.030 And pass. 12:27.230 --> 12:28.030 Let's marry. 12:30.110 --> 12:30.390 And. 12:33.470 --> 12:36.310 Okay, let me show you. 12:36.910 --> 12:37.470 What? 12:40.970 --> 12:41.650 Let me say. 12:44.090 --> 12:46.370 Uh, we have some error. 12:48.250 --> 12:49.810 Numeric number. 12:51.290 --> 12:52.010 Integer. 12:57.650 --> 13:03.170 Limit one to say we have our internal several. 13:06.490 --> 13:08.530 Override our internal server. 13:09.730 --> 13:15.210 Because right here we have a complete the transform detail. 13:15.250 --> 13:20.450 Let let me comment that also I will show you how we can fix that. 13:25.730 --> 13:32.450 Now let's say if I say we the limit will be one, we only get the one thing okay. 13:33.530 --> 13:41.440 And right here we don't have a cursor, All right, we need to return the cursor. 13:41.840 --> 13:44.880 Also the cursor right here. 13:44.880 --> 13:46.680 It will come from the last item. 13:47.360 --> 13:48.040 The last item. 13:48.080 --> 13:48.880 Let me show you. 13:51.480 --> 13:57.640 Sorry about the lag one dot created, huh? 13:58.280 --> 13:58.640 Okay. 13:58.640 --> 14:02.800 We need to return the cursor from the last one. 14:04.840 --> 14:10.640 Right now it's a created app dot exit on file right here. 14:11.880 --> 14:13.480 What about the schema? 14:14.040 --> 14:15.880 The reason we call the boss right here. 14:15.920 --> 14:20.720 It don't have created app field. 14:21.400 --> 14:24.800 So I think I will provide right here. 14:25.120 --> 14:25.640 Okay. 14:26.440 --> 14:28.360 We already have a timestamp. 14:28.360 --> 14:28.840 Right. 14:29.560 --> 14:31.360 But let us. 14:36.710 --> 14:38.950 Only for TypeScript once. 14:39.150 --> 14:42.190 We don't need to boost the problem here. 14:42.470 --> 14:42.950 Okay. 14:43.110 --> 14:46.870 Because we already have a timestamp from the schema. 14:47.270 --> 14:47.590 Okay. 14:47.630 --> 14:49.910 This is just add a little bit of TypeScript. 14:50.990 --> 14:52.990 Now it will fit TypeScript right? 14:53.390 --> 14:54.350 Let me show you. 14:55.430 --> 15:00.030 Now you can see this is the cursor right. 15:00.070 --> 15:04.110 I want it will return the cursor for me. 15:04.950 --> 15:05.470 Okay. 15:05.750 --> 15:07.590 Now you can see this is the cursor. 15:08.630 --> 15:08.910 Okay. 15:08.910 --> 15:09.910 This is the cursor. 15:10.510 --> 15:10.950 Right. 15:11.510 --> 15:17.830 And in the next one, in order to vaccination I will put the cursor right here. 15:21.510 --> 15:27.590 In the stage and say now you can say with certainty it will return from another culture. 15:27.830 --> 15:30.910 And right now the database will be full. 15:30.950 --> 15:35.380 This means we don't have any bias anymore, right? 15:35.980 --> 15:44.020 So with this approach we can create the pagination using the cursor technique. 15:44.060 --> 15:46.620 And it's very good for performance. 15:47.540 --> 15:56.180 But what if and if you don't understand my explanation please check out the code. 15:56.340 --> 16:01.740 And I'm sure you will because it doesn't hurt at all, right? 16:02.740 --> 16:06.220 So it still is a right. 16:07.500 --> 16:09.220 It's just the whole idea. 16:09.620 --> 16:17.100 We need to leverage and shortcut using the created art field. 16:17.860 --> 16:19.700 Okay, to do the pagination. 16:21.100 --> 16:22.660 And one more thing. 16:22.660 --> 16:25.860 We need to fix the radio. 16:27.700 --> 16:28.700 Let me open again. 16:42.930 --> 16:50.090 GitHub internal server error because in the most of it we already return the object. 16:50.130 --> 16:50.610 Okay. 16:51.410 --> 16:56.970 So we need to configuration a little bit inside Respondto. 16:57.330 --> 16:59.890 Also inside the transform DTO. 16:59.930 --> 17:02.690 Over here we have a map. 17:03.210 --> 17:04.970 Right now let me console.log. 17:04.970 --> 17:06.690 What is inside the data. 17:27.250 --> 17:30.890 Right here we have a little bit error. 17:31.880 --> 17:36.320 High altitude sky, which we should call. 17:36.320 --> 17:50.080 This will be the data because for example, in in later if we have another uh, resource can pagination. 17:50.360 --> 17:53.280 If we do the post we cannot reduce that. 17:53.640 --> 17:54.080 Okay. 17:54.320 --> 17:57.040 But let me show you what exactly what I mean. 17:57.080 --> 18:01.680 For example, right here I will use the boss and inside the chart for me. 18:01.680 --> 18:04.520 So let me go for use. 18:06.360 --> 18:07.320 I will say it again. 18:08.640 --> 18:12.560 We got the error but we already get the data right. 18:14.680 --> 18:21.240 So here we will based on this field to know which will be the visualization or not, I will just give 18:21.240 --> 18:24.120 the data has own property. 18:26.920 --> 18:37.310 We will pass next by if it has led by it means this is the end point for the pagination, right? 18:37.350 --> 18:39.790 So for that reason we need to return over here. 18:41.430 --> 18:45.150 And uh data. 18:45.190 --> 18:47.630 Data right here. 18:47.630 --> 18:49.030 We need to destructuring. 18:56.030 --> 19:00.550 Now for our data we have a post right. 19:00.590 --> 19:15.750 We would go here and we need to pass the past next by and closure over here. 19:21.550 --> 19:21.950 Right. 19:21.950 --> 19:22.950 Something like that. 19:23.510 --> 19:25.150 And we have some error. 19:26.270 --> 19:31.340 We we need to use Roberto Tato has own property. 19:32.140 --> 19:32.460 Okay. 19:32.500 --> 19:32.900 Okay. 19:33.660 --> 19:37.260 We can use object dot. 19:37.260 --> 19:44.020 Prototype dot has own property and we can call. 19:46.580 --> 19:53.980 Him with the data and the field will be displaced by. 19:54.340 --> 19:54.620 Okay. 19:54.660 --> 19:56.740 It is exactly the same as before. 19:57.100 --> 20:00.060 But this is the better in JavaScript. 20:06.220 --> 20:07.180 Let me say it again. 20:09.380 --> 20:11.340 Now we already got message. 20:11.540 --> 20:11.940 Okay. 20:11.980 --> 20:18.740 And we already provide a field for husk nest base and closure okay. 20:20.860 --> 20:23.300 So this is what happens if I move this thing. 20:23.460 --> 20:23.940 So. 20:29.850 --> 20:32.810 Okay, we got the internal server error. 20:37.930 --> 20:41.050 Let me test again a little bit more here. 20:41.770 --> 20:42.410 It's work. 20:42.450 --> 20:45.330 But if I move the cursor over here. 20:47.770 --> 20:51.970 So what it is that we need to check a little bit over here. 20:53.130 --> 20:56.330 Let's say we cannot wait for the uploaded file. 20:59.570 --> 21:00.170 Right. 21:00.730 --> 21:07.730 So for that reason, we need to check if has led by a withdrawal. 21:08.210 --> 21:10.930 We will have a created app. 21:10.970 --> 21:13.810 If not, we can put a note over here. 21:25.050 --> 21:26.790 So it was more better. 21:27.070 --> 21:29.350 And I think this will be very enough. 21:30.190 --> 21:30.670 Okay. 21:30.710 --> 21:34.630 You can check that if you want. 21:35.510 --> 21:38.190 You can add a little bit of validation if you want. 21:38.230 --> 21:41.590 But I think now you got the idea right. 21:41.990 --> 21:42.830 So let's see what. 21:42.830 --> 21:46.990 That's it and try to understand that. 21:47.990 --> 21:51.190 And uh with this thing it's very easy, right? 21:52.550 --> 21:53.950 We just need to add a little bit. 21:54.390 --> 21:59.710 But like I said, if we call this here will be the post. 22:00.190 --> 22:03.470 It cannot reduce it later. 22:03.990 --> 22:04.510 Right. 22:04.950 --> 22:10.870 Because for example, in later we have uh. 22:13.910 --> 22:20.870 For example like the user roles or command or something like that. 22:21.590 --> 22:22.110 Okay. 22:22.230 --> 22:30.900 How do we Reviews so far is that we need to rename a little bit and in later make sure we always use 22:30.900 --> 22:31.540 nickname. 22:31.860 --> 22:36.060 I will call the items and right here we check it to. 22:38.620 --> 22:39.100 Boost. 22:39.100 --> 22:42.100 The item over here is much more better right? 22:43.700 --> 22:45.340 This is the generic name. 22:46.020 --> 22:46.540 Okay. 22:50.620 --> 22:53.340 Let me say this. 22:53.340 --> 22:55.780 The work pathway is okay. 22:59.500 --> 23:01.660 And right now we have one more problem. 23:03.700 --> 23:09.140 If we don't put anything inside here. 23:11.540 --> 23:17.300 It will console.log the empty string. 23:33.650 --> 23:36.090 So the reason is very simple. 23:36.450 --> 23:42.090 The reason because the validation rule before it adds the default value. 23:42.410 --> 23:50.650 So validation before routine we can move the default value higher. 23:51.290 --> 23:51.810 Okay. 23:52.570 --> 23:54.450 We can move the new operator. 23:55.610 --> 23:56.330 Let me say. 23:59.010 --> 24:02.250 We value we can move ten over here. 24:03.090 --> 24:06.010 And let's try to remove that. 24:09.650 --> 24:16.410 If we don't put anything let's say let y be same again. 24:17.770 --> 24:18.210 Okay. 24:18.210 --> 24:20.610 We already got information. 24:20.960 --> 24:23.840 and hustled by for sure will be false. 24:23.880 --> 24:26.200 And Kershaw will be low. 24:26.240 --> 24:26.760 Right. 24:32.480 --> 24:33.160 Now is. 24:37.880 --> 24:39.920 Let me test one more time. 24:40.600 --> 24:48.080 Will make only one say we got to console and that will be true. 24:48.720 --> 24:50.120 Put the console over here. 25:02.720 --> 25:03.280 Okay. 25:05.480 --> 25:07.400 This orderly woke up. 25:07.400 --> 25:08.360 We spotted. 25:09.080 --> 25:12.040 And thus, for the video. 25:12.240 --> 25:17.880 I hope you understand and talk a little bit of time to understand. 25:19.320 --> 25:20.040 I will see you.