1 00:00:01,254 --> 00:00:03,100 ‫In this lecture I want to show you 2 00:00:03,100 --> 00:00:06,373 ‫a couple of different things involving modules. 3 00:00:07,720 --> 00:00:11,220 ‫And I want to start by basically proving to you 4 00:00:11,220 --> 00:00:15,300 ‫that Node does in fact wrap the code in our modules 5 00:00:15,300 --> 00:00:17,270 ‫into a wrapper function, 6 00:00:17,270 --> 00:00:19,420 ‫like I showed you in the last lecture. 7 00:00:19,420 --> 00:00:24,043 ‫So let's create a new file again, module.js, 8 00:00:25,270 --> 00:00:28,543 ‫and that's modules, like this. 9 00:00:29,900 --> 00:00:31,740 ‫Okay, and what I'm gonna do here 10 00:00:31,740 --> 00:00:36,703 ‫is to log to the console the arguments, okay? 11 00:00:38,480 --> 00:00:42,170 ‫So arguments is an array in JavaScript, 12 00:00:42,170 --> 00:00:44,490 ‫and this array contains all the values 13 00:00:44,490 --> 00:00:47,100 ‫that were passed into a function. 14 00:00:47,100 --> 00:00:50,490 ‫So when I log this arguments array to the console, 15 00:00:50,490 --> 00:00:53,110 ‫if we actually see some values there, well, 16 00:00:53,110 --> 00:00:57,670 ‫then it means that we're really in a function, okay? 17 00:00:57,670 --> 00:01:00,633 ‫So let's run modules. 18 00:01:01,530 --> 00:01:06,530 ‫And indeed, here we have the code in our arguments. 19 00:01:06,770 --> 00:01:09,050 ‫And so let's remember the five arguments 20 00:01:09,050 --> 00:01:10,760 ‫of the wrapper function. 21 00:01:10,760 --> 00:01:13,720 ‫The first one is the export, so this one, 22 00:01:13,720 --> 00:01:14,790 ‫which is currently empty 23 00:01:14,790 --> 00:01:17,030 ‫because we're not exporting anything. 24 00:01:17,030 --> 00:01:19,560 ‫The second one is the require function, 25 00:01:19,560 --> 00:01:20,670 ‫so we can see that here, 26 00:01:20,670 --> 00:01:23,100 ‫we have the require function indeed. 27 00:01:23,100 --> 00:01:26,673 ‫Then the third one is called module, okay. 28 00:01:28,280 --> 00:01:31,420 ‫And in module we have then module exports, 29 00:01:31,420 --> 00:01:34,100 ‫which again we talked about in the last lecture. 30 00:01:34,100 --> 00:01:37,250 ‫And what do we have here is not that important, again, 31 00:01:37,250 --> 00:01:38,520 ‫I just wanted to show you 32 00:01:38,520 --> 00:01:41,570 ‫that we're actually in a function right now, 33 00:01:41,570 --> 00:01:43,750 ‫so that all this code that we have in this module 34 00:01:43,750 --> 00:01:47,660 ‫is indeed wrapped into this wrapper function, okay? 35 00:01:47,660 --> 00:01:50,980 ‫Then number three and number four are the filename 36 00:01:50,980 --> 00:01:52,640 ‫and the directory name. 37 00:01:52,640 --> 00:01:56,735 ‫And indeed, this is the name of the module 38 00:01:56,735 --> 00:01:59,260 ‫that we're currently in, so modules.js. 39 00:01:59,260 --> 00:02:02,450 ‫And then here we have the directory name. 40 00:02:02,450 --> 00:02:03,550 ‫So I'm on my desktop, 41 00:02:03,550 --> 00:02:05,970 ‫and then in this now Node works folder. 42 00:02:05,970 --> 00:02:07,740 ‫So similar to this one here, 43 00:02:07,740 --> 00:02:11,970 ‫but then this one has slash the module name, okay? 44 00:02:11,970 --> 00:02:14,250 ‫So that proves us that, indeed, 45 00:02:14,250 --> 00:02:16,800 ‫all the code inside a module is wrapped, 46 00:02:16,800 --> 00:02:20,490 ‫and that we have access to all these variables, 47 00:02:20,490 --> 00:02:23,030 ‫so these arguments, okay? 48 00:02:23,030 --> 00:02:25,640 ‫So I just find this an interesting experiment 49 00:02:25,640 --> 00:02:26,960 ‫that we can do. 50 00:02:26,960 --> 00:02:29,860 ‫And we can actually do another cool thing. 51 00:02:29,860 --> 00:02:32,980 ‫So to actually show you the wrapper function, 52 00:02:32,980 --> 00:02:37,980 ‫we can require the module module, okay. 53 00:02:38,300 --> 00:02:40,200 ‫So there's a module called module, 54 00:02:40,200 --> 00:02:44,410 ‫which we actually never used but internally Node uses it. 55 00:02:44,410 --> 00:02:47,190 ‫And in there we have the wrapper. 56 00:02:47,190 --> 00:02:49,290 ‫And so that is actually this property 57 00:02:49,290 --> 00:02:51,030 ‫is actually the wrapper function. 58 00:02:51,030 --> 00:02:52,730 ‫So we can now take a look at that. 59 00:02:57,410 --> 00:03:00,140 ‫And where is that, ah, yeah. 60 00:03:00,140 --> 00:03:01,720 ‫So here, here it is actually. 61 00:03:01,720 --> 00:03:04,410 ‫So this is the wrapper function. 62 00:03:04,410 --> 00:03:06,650 ‫And so indeed you see export, require, 63 00:03:06,650 --> 00:03:09,800 ‫module, filename and directory name, 64 00:03:09,800 --> 00:03:11,160 ‫and then the function body. 65 00:03:11,160 --> 00:03:13,520 ‫And so this is what Node internally use, 66 00:03:13,520 --> 00:03:16,220 ‫so basically this template here, it uses it, 67 00:03:16,220 --> 00:03:20,060 ‫and then fills up the body of this function with our code. 68 00:03:20,060 --> 00:03:23,260 ‫Okay, so again, just an interesting experiment here. 69 00:03:23,260 --> 00:03:25,260 ‫Now the most important thing that I wanna show you here 70 00:03:25,260 --> 00:03:27,960 ‫is how we can export and import data 71 00:03:27,960 --> 00:03:30,370 ‫from one module into the other. 72 00:03:30,370 --> 00:03:33,130 ‫And so let's start by creating a new module here, 73 00:03:33,130 --> 00:03:35,280 ‫in which I'm gonna create a calculator, 74 00:03:35,280 --> 00:03:38,040 ‫a bit like I mentioned in the last video. 75 00:03:38,040 --> 00:03:42,180 ‫So let's just call this test-module-1, 76 00:03:42,180 --> 00:03:44,393 ‫because we're gonna have a couple of them. 77 00:03:45,300 --> 00:03:47,763 ‫And here I'm gonna create a calculator class. 78 00:03:49,810 --> 00:03:52,890 ‫So again, this is the ES6 syntax 79 00:03:52,890 --> 00:03:56,053 ‫of writing classes in JavaScript. 80 00:03:57,260 --> 00:04:01,033 ‫So let's add a couple of methods here, so add a and b, 81 00:04:04,760 --> 00:04:08,100 ‫will of course return a plus b, 82 00:04:08,100 --> 00:04:12,920 ‫so very simple stuff, multiply a, b, 83 00:04:14,020 --> 00:04:17,317 ‫will return a times b, and then just, 84 00:04:21,785 --> 00:04:22,950 ‫let's just do divide as well, 85 00:04:22,950 --> 00:04:26,580 ‫just for the sake of completeness here, a, b, like this. 86 00:04:29,470 --> 00:04:32,170 ‫Give it a save, it nicely formats it, 87 00:04:32,170 --> 00:04:36,420 ‫and now we can do module.exports, 88 00:04:36,420 --> 00:04:38,370 ‫just like we learned in the last video, 89 00:04:39,970 --> 00:04:42,690 ‫and we're exporting our calculator, okay? 90 00:04:42,690 --> 00:04:45,000 ‫So again, we use module.exports 91 00:04:45,000 --> 00:04:48,010 ‫when we want to export one single value. 92 00:04:48,010 --> 00:04:49,830 ‫And in this case our single value here 93 00:04:49,830 --> 00:04:51,660 ‫is the calculator class. 94 00:04:51,660 --> 00:04:55,180 ‫So module.exports is exactly what is returned 95 00:04:55,180 --> 00:04:58,340 ‫from one module, so whatever we put there, well, 96 00:04:58,340 --> 00:05:01,320 ‫then gets exported automatically, right? 97 00:05:01,320 --> 00:05:03,460 ‫We can then save the exported value 98 00:05:03,460 --> 00:05:07,023 ‫to a variable when importing it, so let's do that now. 99 00:05:08,540 --> 00:05:12,070 ‫And now here we can actually give it any name that we want. 100 00:05:12,070 --> 00:05:15,390 ‫So the name that we are exporting on the other side, 101 00:05:15,390 --> 00:05:17,380 ‫so in this other module, doesn't matter. 102 00:05:17,380 --> 00:05:19,363 ‫We can call it anything we want here. 103 00:05:20,810 --> 00:05:24,150 ‫So in that sense it's just like a normal function return, 104 00:05:24,150 --> 00:05:26,400 ‫right, so we can always return any variable, 105 00:05:26,400 --> 00:05:28,320 ‫but then call it something else 106 00:05:28,320 --> 00:05:31,590 ‫when we basically save the result of a function 107 00:05:31,590 --> 00:05:33,023 ‫to a variable, right? 108 00:05:34,580 --> 00:05:36,780 ‫So since it's our own module, 109 00:05:36,780 --> 00:05:41,780 ‫we have to use the dot slash, so what I did just here, 110 00:05:42,010 --> 00:05:44,600 ‫and then test-module-1. 111 00:05:44,600 --> 00:05:47,830 ‫And the JS, remember, we can just drop that, 112 00:05:47,830 --> 00:05:49,990 ‫it's not necessary, okay? 113 00:05:49,990 --> 00:05:53,560 ‫And so this C variable here, which is uppercase 114 00:05:53,560 --> 00:05:57,330 ‫because for class we usually always use uppercase names. 115 00:05:57,330 --> 00:06:01,000 ‫And remember, we are actually exporting a class here. 116 00:06:01,000 --> 00:06:04,783 ‫Okay, so we can now use that class to do some calculations. 117 00:06:06,230 --> 00:06:08,853 ‫So first of all let's create a new calculator, 118 00:06:10,200 --> 00:06:12,650 ‫calculator one, because later on 119 00:06:12,650 --> 00:06:15,090 ‫we're gonna have another one, okay? 120 00:06:15,090 --> 00:06:18,650 ‫And so now we create a new instance 121 00:06:18,650 --> 00:06:20,500 ‫of a calculator like this, 122 00:06:20,500 --> 00:06:23,290 ‫and this should be nothing new for you at this point. 123 00:06:23,290 --> 00:06:25,900 ‫And then let's log through console 124 00:06:25,900 --> 00:06:27,793 ‫the result of actually using this. 125 00:06:28,850 --> 00:06:33,850 ‫So calc1.add, and let's say two and five. 126 00:06:37,210 --> 00:06:40,443 ‫Give it a save, and actually let's comment out these two. 127 00:06:42,550 --> 00:06:45,920 ‫Save it again, and then Node modules, 128 00:06:45,920 --> 00:06:47,940 ‫and here we have the result, seven. 129 00:06:47,940 --> 00:06:51,900 ‫So that's two plus five, so it works, right? 130 00:06:51,900 --> 00:06:54,290 ‫And here in our test module, 131 00:06:54,290 --> 00:06:57,970 ‫we could actually do it in a more elegant way. 132 00:06:57,970 --> 00:07:00,300 ‫So we could assign this class here directly 133 00:07:00,300 --> 00:07:03,190 ‫to module.exports, right? 134 00:07:03,190 --> 00:07:06,270 ‫So right now we have a class declaration, 135 00:07:06,270 --> 00:07:08,570 ‫so that's a little bit like a function declaration, 136 00:07:08,570 --> 00:07:12,200 ‫where we say function calculator, and then this, 137 00:07:12,200 --> 00:07:14,870 ‫and here we say class, okay? 138 00:07:14,870 --> 00:07:18,520 ‫But we could do it with a class expression as well. 139 00:07:18,520 --> 00:07:22,050 ‫And so like this we simply don't use 140 00:07:22,050 --> 00:07:23,660 ‫the calculator name anyway. 141 00:07:23,660 --> 00:07:25,023 ‫So copy it, comment it out. 142 00:07:28,450 --> 00:07:30,760 ‫Okay, so just like this. 143 00:07:30,760 --> 00:07:32,650 ‫So we just say that this is a class, 144 00:07:32,650 --> 00:07:34,970 ‫and then assign it to a variable. 145 00:07:34,970 --> 00:07:36,593 ‫And so that's now an expression. 146 00:07:37,600 --> 00:07:39,470 ‫So let's run this again, 147 00:07:39,470 --> 00:07:43,120 ‫and we see of course our seven again, okay? 148 00:07:43,120 --> 00:07:47,471 ‫So again, this is just to actually immediately assign 149 00:07:47,471 --> 00:07:50,520 ‫the value that we want to module.exports, 150 00:07:50,520 --> 00:07:53,280 ‫and that's gonna save us then some lines of code, 151 00:07:53,280 --> 00:07:56,473 ‫and probably make our code look a bit better. 152 00:07:57,390 --> 00:08:01,590 ‫Okay, so that's how we export stuff with module.exports, 153 00:08:01,590 --> 00:08:05,160 ‫and now let's see how and when we can use 154 00:08:05,160 --> 00:08:07,820 ‫the exports shorthand that I also mentioned 155 00:08:07,820 --> 00:08:08,973 ‫in the previous video. 156 00:08:10,970 --> 00:08:14,433 ‫So let's just create a simple comment here, module.exports. 157 00:08:16,930 --> 00:08:19,300 ‫Then here just exports. 158 00:08:19,300 --> 00:08:24,300 ‫So a new module test, and again, module-2.js. 159 00:08:27,930 --> 00:08:31,790 ‫And so the alternative for doing module.exports 160 00:08:31,790 --> 00:08:36,120 ‫is to add properties to the exports object itself. 161 00:08:36,120 --> 00:08:37,680 ‫So we could do it like this, 162 00:08:37,680 --> 00:08:40,740 ‫and using again the calculator example from before, 163 00:08:40,740 --> 00:08:42,410 ‫we could do it like this. 164 00:08:42,410 --> 00:08:46,253 ‫So we can simply add properties to the exports object. 165 00:08:48,640 --> 00:08:53,640 ‫So a and b will return a plus b, 166 00:08:54,490 --> 00:08:59,490 ‫exports.multiply a, b will return a times b, 167 00:09:06,880 --> 00:09:08,280 ‫and now let's just duplicate 168 00:09:10,730 --> 00:09:15,690 ‫just for the sake of completeness again, and okay. 169 00:09:15,690 --> 00:09:18,600 ‫So we created basically three anonymous functions here, 170 00:09:18,600 --> 00:09:20,720 ‫these three, and assigned them 171 00:09:20,720 --> 00:09:24,190 ‫to three properties of exports. 172 00:09:24,190 --> 00:09:27,750 ‫And so now when we export this module on the other side, 173 00:09:27,750 --> 00:09:31,400 ‫so in modules.js, we will get basically access 174 00:09:31,400 --> 00:09:34,230 ‫to this exports object. 175 00:09:34,230 --> 00:09:36,290 ‫So let me show that to you. 176 00:09:36,290 --> 00:09:38,820 ‫So let's say const calc2 is require. 177 00:09:43,490 --> 00:09:46,640 ‫Again, don't forget the dot and slash, 178 00:09:46,640 --> 00:09:48,683 ‫because it is our own module. 179 00:09:50,400 --> 00:09:55,400 ‫Okay, and so now this calc2 here is the exports object. 180 00:09:55,940 --> 00:09:58,800 ‫Okay, so let me show that to you. 181 00:09:58,800 --> 00:10:03,207 ‫Console.log, calc2.add, two and five. 182 00:10:06,670 --> 00:10:09,823 ‫So that should give us the exact same result as before. 183 00:10:11,870 --> 00:10:15,313 ‫And indeed, here is our seven, just like before. 184 00:10:16,997 --> 00:10:18,147 ‫And if we did multiply, 185 00:10:20,240 --> 00:10:24,000 ‫well then that should be of course 10. 186 00:10:24,000 --> 00:10:26,820 ‫And so yeah, we have seven here from the addition here, 187 00:10:26,820 --> 00:10:28,793 ‫and then this multiply gives us 10. 188 00:10:29,660 --> 00:10:31,460 ‫So I hope that this really makes a difference 189 00:10:31,460 --> 00:10:34,370 ‫between module.exports and exports clear. 190 00:10:34,370 --> 00:10:37,150 ‫And so again, when we're using simply exports, 191 00:10:37,150 --> 00:10:41,360 ‫we can add stuff to this object, so basically properties, 192 00:10:41,360 --> 00:10:43,470 ‫and then when we import that, 193 00:10:43,470 --> 00:10:45,900 ‫so when we require this module, 194 00:10:45,900 --> 00:10:47,340 ‫the result that we're gonna get 195 00:10:47,340 --> 00:10:50,400 ‫is an object containing all these properties. 196 00:10:50,400 --> 00:10:52,180 ‫And since we're getting an object, 197 00:10:52,180 --> 00:10:55,260 ‫we can use the power of ES6 destructuring 198 00:10:55,260 --> 00:10:58,023 ‫to do some cool magic here, basically. 199 00:10:59,000 --> 00:11:02,843 ‫So let me get rid of this one, or actually duplicate it, 200 00:11:03,710 --> 00:11:07,690 ‫comment out this one, and so we can use destructuring 201 00:11:07,690 --> 00:11:12,130 ‫to destructure the object that we get, okay? 202 00:11:12,130 --> 00:11:16,140 ‫And it works like this, so we use the curly braces, 203 00:11:16,140 --> 00:11:18,200 ‫and then we simply create variable names 204 00:11:18,200 --> 00:11:21,460 ‫for the properties in that object. 205 00:11:21,460 --> 00:11:26,460 ‫So again, let's use add, multiply and divide. 206 00:11:26,860 --> 00:11:30,380 ‫So that are the names that we actually have 207 00:11:30,380 --> 00:11:32,450 ‫on this exports object. 208 00:11:32,450 --> 00:11:34,680 ‫So add, multiply and divide, 209 00:11:34,680 --> 00:11:37,080 ‫and these actually have to be the exact same name 210 00:11:37,080 --> 00:11:39,330 ‫as in the original object, okay? 211 00:11:39,330 --> 00:11:41,100 ‫Now the thing that this will do 212 00:11:41,100 --> 00:11:43,960 ‫is that basically it will create a variable 213 00:11:43,960 --> 00:11:45,523 ‫called simply multiply. 214 00:11:47,820 --> 00:11:50,400 ‫And so indeed, here is our result. 215 00:11:50,400 --> 00:11:53,980 ‫And we can actually only import the ones that we want. 216 00:11:53,980 --> 00:11:57,470 ‫So let's say we only want add and multiply, okay? 217 00:11:57,470 --> 00:12:00,290 ‫And so we will only get access to these two, 218 00:12:00,290 --> 00:12:03,340 ‫instead of importing everything from the module. 219 00:12:03,340 --> 00:12:05,160 ‫And this is quite a common pattern 220 00:12:05,160 --> 00:12:07,240 ‫that you will see used in Node, 221 00:12:07,240 --> 00:12:09,930 ‫and we will do that throughout the project as well. 222 00:12:09,930 --> 00:12:11,630 ‫Okay, so in this video we talked 223 00:12:11,630 --> 00:12:14,030 ‫about the wrapper function here, 224 00:12:14,030 --> 00:12:16,280 ‫then we talked about exporting and importing 225 00:12:16,280 --> 00:12:20,110 ‫using module.exports and the exports shorthand. 226 00:12:20,110 --> 00:12:21,810 ‫And now finally, just to finish, 227 00:12:21,810 --> 00:12:24,523 ‫let's talk about caching very quickly. 228 00:12:27,060 --> 00:12:30,143 ‫Okay, so let's create test-module-3 here. 229 00:12:35,860 --> 00:12:39,603 ‫And what I'm gonna do here is to create a console.log, 230 00:12:41,070 --> 00:12:44,193 ‫so basically some top-level code inside this module. 231 00:12:46,710 --> 00:12:49,793 ‫Hello from the module, okay, 232 00:12:50,892 --> 00:12:53,973 ‫and then I also want to export a function. 233 00:12:54,830 --> 00:12:58,770 ‫Just one single function, and so I'm saying module.exports 234 00:13:00,920 --> 00:13:05,920 ‫equals function without any arguments, 235 00:13:06,300 --> 00:13:08,300 ‫one that will simply log to the console: 236 00:13:10,110 --> 00:13:13,673 ‫log this beautiful text. 237 00:13:14,920 --> 00:13:17,883 ‫Just some small emoji here to make it pop a little bit. 238 00:13:20,210 --> 00:13:25,133 ‫Okay, so let's now require this test module. 239 00:13:28,170 --> 00:13:32,070 ‫Test-module-3, and I'm not saving it to any variable. 240 00:13:32,070 --> 00:13:34,750 ‫Instead I'm going to call the function right away 241 00:13:34,750 --> 00:13:37,250 ‫without saving it to a variable. 242 00:13:37,250 --> 00:13:38,860 ‫So we could of course do that, 243 00:13:38,860 --> 00:13:41,530 ‫then we would have the function in a variable, 244 00:13:41,530 --> 00:13:43,070 ‫and we could then call it. 245 00:13:43,070 --> 00:13:45,070 ‫But this is the exact same thing, 246 00:13:45,070 --> 00:13:48,530 ‫because this will return this function that we defined, 247 00:13:48,530 --> 00:13:50,630 ‫so this one here, right? 248 00:13:50,630 --> 00:13:53,610 ‫It will return this because we are using module.exports, 249 00:13:53,610 --> 00:13:57,727 ‫and then right away we call this function here, okay? 250 00:13:57,727 --> 00:14:00,890 ‫And so actually let's do that three time. 251 00:14:00,890 --> 00:14:04,980 ‫And keeping in mind that we have caching in Node.js modules, 252 00:14:04,980 --> 00:14:08,053 ‫what do you think will happen when we run this code? 253 00:14:09,580 --> 00:14:13,933 ‫Okay, so let's run this and see what's gonna happen. 254 00:14:16,770 --> 00:14:19,460 ‫Here we have the result, hello from the module, 255 00:14:19,460 --> 00:14:22,980 ‫and then three times log this beautiful text. 256 00:14:22,980 --> 00:14:26,520 ‫So we have this logging here three times, well, 257 00:14:26,520 --> 00:14:29,350 ‫because we called the same function three times. 258 00:14:29,350 --> 00:14:33,320 ‫But we have hello from the module only once, okay? 259 00:14:33,320 --> 00:14:35,450 ‫And that is because of caching. 260 00:14:35,450 --> 00:14:38,800 ‫So technically this module was only loaded once, 261 00:14:38,800 --> 00:14:42,850 ‫and so the code inside of it was also executed once only. 262 00:14:42,850 --> 00:14:46,270 ‫And so that's why this line of code here, 263 00:14:46,270 --> 00:14:50,370 ‫this logging was only run once, okay? 264 00:14:50,370 --> 00:14:53,320 ‫And so these other two loggings here, well, 265 00:14:53,320 --> 00:14:56,470 ‫they came from cache, so they were stored somewhere 266 00:14:56,470 --> 00:14:58,610 ‫in the Node's processes cache. 267 00:14:58,610 --> 00:15:01,540 ‫And once we called the function here for the second time, 268 00:15:01,540 --> 00:15:03,390 ‫it was simply retrieved from there, 269 00:15:03,390 --> 00:15:06,520 ‫instead of loading the module again, okay? 270 00:15:06,520 --> 00:15:10,510 ‫So I'm sure that makes a lot of sense to you. 271 00:15:10,510 --> 00:15:13,450 ‫And so that was our lecture, actually. 272 00:15:13,450 --> 00:15:16,090 ‫If you have any questions, you can of course, as always, 273 00:15:16,090 --> 00:15:20,070 ‫post them to the Q&A and you will get help there. 274 00:15:20,070 --> 00:15:23,030 ‫So that finishes this entire section. 275 00:15:23,030 --> 00:15:27,750 ‫I know it was quite of a ride until we got to this point, 276 00:15:27,750 --> 00:15:30,700 ‫so a lot of stuff to take in. 277 00:15:30,700 --> 00:15:33,140 ‫And if you did correct everything 100%, 278 00:15:33,140 --> 00:15:35,240 ‫don't worry all too much about it, 279 00:15:35,240 --> 00:15:36,800 ‫because throughout the course, 280 00:15:36,800 --> 00:15:41,170 ‫most of the stuff will become clear eventually, okay? 281 00:15:41,170 --> 00:15:43,940 ‫So don't worry, just keep moving on in the course, 282 00:15:43,940 --> 00:15:45,790 ‫and I'll see you in the next section.