WEBVTT 1 00:00:00.720 --> 00:00:04.290 Okay, so let's get to work. 2 00:00:04.290 --> 00:00:07.256 So number one is creating 3 00:00:07.256 --> 00:00:08.340 an object 4 00:00:08.340 --> 00:00:10.260 for each of them. 5 00:00:10.260 --> 00:00:11.670 So object 6 00:00:11.670 --> 00:00:12.503 mark. 7 00:00:15.840 --> 00:00:20.433 So full name property, Mark Miller. 8 00:00:21.750 --> 00:00:26.493 Then the mass, which is 78 kilograms. 9 00:00:27.480 --> 00:00:30.180 And then the height, 10 00:00:30.180 --> 00:00:34.050 which is 1.69 meters. 11 00:00:34.050 --> 00:00:36.360 So that's it for now. 12 00:00:36.360 --> 00:00:37.460 And now I'm just gonna 13 00:00:38.550 --> 00:00:39.383 copy this. 14 00:00:40.590 --> 00:00:42.390 As always, I'm a bit lazy 15 00:00:42.390 --> 00:00:45.273 and that's just how programmers are, I guess. 16 00:00:46.530 --> 00:00:48.670 So John Smith 17 00:00:50.550 --> 00:00:54.360 and he is 92 kilos 18 00:00:54.360 --> 00:00:57.903 and 1.95 meters tall. 19 00:00:59.100 --> 00:01:02.640 Okay, so that is point number one. 20 00:01:02.640 --> 00:01:06.250 And now we will create the calcBMI method 21 00:01:11.220 --> 00:01:12.840 And then a function 22 00:01:12.840 --> 00:01:14.550 without any parameters 23 00:01:14.550 --> 00:01:16.230 because we will take the data 24 00:01:16.230 --> 00:01:18.180 directly from the object 25 00:01:18.180 --> 00:01:22.350 just like we did it with the calcH method previously. 26 00:01:22.350 --> 00:01:24.123 And remember that it says here 27 00:01:24.123 --> 00:01:26.502 that we should store the BMI value 28 00:01:26.502 --> 00:01:27.904 to a property 29 00:01:27.904 --> 00:01:30.889 and also return it from the method. 30 00:01:30.889 --> 00:01:34.000 So this means that we will do 31 00:01:35.231 --> 00:01:37.260 this.BMI 32 00:01:37.260 --> 00:01:39.960 and then do the calculation here. 33 00:01:39.960 --> 00:01:43.380 And remember from the formula the BMI is calculated 34 00:01:43.380 --> 00:01:45.248 by this.mass 35 00:01:45.248 --> 00:01:46.890 divided by 36 00:01:46.890 --> 00:01:49.770 this.height 37 00:01:49.770 --> 00:01:50.613 squared. 38 00:01:51.690 --> 00:01:53.965 So exponentiation operator 39 00:01:53.965 --> 00:01:55.090 with two 40 00:01:56.190 --> 00:01:58.650 and then also return it. 41 00:01:58.650 --> 00:02:00.160 So this.bmi 42 00:02:02.337 --> 00:02:05.742 and just to see if this actually works 43 00:02:05.742 --> 00:02:08.433 let's actually call this method. 44 00:02:10.175 --> 00:02:12.780 So mark.calc.BMI. 45 00:02:12.780 --> 00:02:15.990 And now I will quickly lock to the console 46 00:02:15.990 --> 00:02:18.330 the property that we just created. 47 00:02:18.330 --> 00:02:20.610 So I could have locked 48 00:02:20.610 --> 00:02:22.410 this to the console directly 49 00:02:22.410 --> 00:02:24.513 but I want to do it this way now 50 00:02:24.513 --> 00:02:26.790 and it doesn't really matter. 51 00:02:26.790 --> 00:02:29.290 So with this, remember we created 52 00:02:30.270 --> 00:02:32.310 a property called BMI 53 00:02:32.310 --> 00:02:35.010 and so that is now of course accessible here. 54 00:02:35.010 --> 00:02:37.170 So mark.bmi 55 00:02:37.170 --> 00:02:39.360 because remember 56 00:02:39.360 --> 00:02:40.481 that here in this method 57 00:02:40.481 --> 00:02:42.579 this now points to mark 58 00:02:42.579 --> 00:02:45.228 because that is the object 59 00:02:45.228 --> 00:02:47.490 that is calling the method 60 00:02:47.490 --> 00:02:51.930 and therefore this.bmi will be on mark. 61 00:02:51.930 --> 00:02:55.060 So mark.bmi equals mark.mass 62 00:02:56.610 --> 00:02:58.920 divided by mark.height. 63 00:02:58.920 --> 00:03:01.440 And so that's how we get this data 64 00:03:01.440 --> 00:03:02.733 into this method. 65 00:03:05.010 --> 00:03:05.843 Alright, 66 00:03:05.843 --> 00:03:07.290 so that's essentially what we learned 67 00:03:07.290 --> 00:03:08.730 in the last lecture. 68 00:03:08.730 --> 00:03:10.200 And so here I'm doing the same. 69 00:03:10.200 --> 00:03:12.330 I'm first calculating this value 70 00:03:12.330 --> 00:03:14.910 and then I'm doing mark.bmi 71 00:03:14.910 --> 00:03:18.027 which was added here in this method call. 72 00:03:18.027 --> 00:03:20.880 Of course, without this method call 73 00:03:20.880 --> 00:03:23.640 mark.bmi would not be available 74 00:03:23.640 --> 00:03:24.900 because this method here 75 00:03:24.900 --> 00:03:26.250 doesn't call itself. 76 00:03:26.250 --> 00:03:28.173 We need to explicitly call it. 77 00:03:29.913 --> 00:03:31.830 Now console 78 00:03:31.830 --> 00:03:33.743 ah, missing the .log. 79 00:03:33.743 --> 00:03:37.630 How can that still happen after all these years? 80 00:03:37.630 --> 00:03:41.304 Okay, so here we get the BMI of 27 81 00:03:41.304 --> 00:03:44.400 which seems about right. 82 00:03:44.400 --> 00:03:47.400 And now as I said, we will simply go ahead 83 00:03:47.400 --> 00:03:49.050 and copy this method 84 00:03:49.050 --> 00:03:50.440 exactly the same 85 00:03:51.390 --> 00:03:54.360 to this John object 86 00:03:54.360 --> 00:03:55.440 and it will work 87 00:03:55.440 --> 00:03:57.646 just the same, believe me. 88 00:03:57.646 --> 00:03:59.823 So let me show that to you. 89 00:04:01.260 --> 00:04:02.516 So now 90 00:04:02.516 --> 00:04:04.200 we call 91 00:04:04.200 --> 00:04:06.630 john.calcBMI. 92 00:04:06.630 --> 00:04:11.010 And so now the object calling calcBMI is John. 93 00:04:11.010 --> 00:04:13.080 And so now in this method here 94 00:04:13.080 --> 00:04:16.410 this will point to the John object. 95 00:04:16.410 --> 00:04:19.290 And so this time John.bmi will be 96 00:04:19.290 --> 00:04:23.313 calculated using John's data of mass and height. 97 00:04:24.480 --> 00:04:25.440 Okay, 98 00:04:25.440 --> 00:04:27.720 are you still following that? 99 00:04:27.720 --> 00:04:29.771 As always, you can pause the video 100 00:04:29.771 --> 00:04:31.957 analyze the code on your own 101 00:04:31.957 --> 00:04:34.056 or you can always rewind 102 00:04:34.056 --> 00:04:36.870 to hear the explanation again. 103 00:04:36.870 --> 00:04:38.580 I actually like to do that myself 104 00:04:38.580 --> 00:04:41.569 when I watch other online video courses. 105 00:04:41.569 --> 00:04:44.827 So I think that's a good tip maybe. 106 00:04:44.827 --> 00:04:47.700 Anyway, so we just calculated 107 00:04:47.700 --> 00:04:50.269 the BMI of John here as well. 108 00:04:50.269 --> 00:04:51.697 And so now I'm logging 109 00:04:51.697 --> 00:04:53.160 both to the console. 110 00:04:53.160 --> 00:04:54.928 And so yeah, 111 00:04:54.928 --> 00:04:57.218 this one also looks correct. 112 00:04:57.218 --> 00:05:01.145 And so this means that simply copying this method 113 00:05:01.145 --> 00:05:02.790 from one place to the other 114 00:05:02.790 --> 00:05:04.323 actually makes it work 115 00:05:04.323 --> 00:05:08.067 and adapt to the data of each object. 116 00:05:08.067 --> 00:05:10.383 Now having the exact same code 117 00:05:10.383 --> 00:05:12.159 in both of these objects 118 00:05:12.159 --> 00:05:15.947 kind of violates the don't repeat yourself principle, 119 00:05:15.947 --> 00:05:16.780 right? 120 00:05:16.780 --> 00:05:18.924 And actually there is a way 121 00:05:18.924 --> 00:05:21.060 in which we can avoid this. 122 00:05:21.060 --> 00:05:22.818 And of course we will learn how 123 00:05:22.818 --> 00:05:24.968 at a later point in the course 124 00:05:24.968 --> 00:05:26.446 using something called 125 00:05:26.446 --> 00:05:28.980 object-oriented programming. 126 00:05:28.980 --> 00:05:30.881 But for now we are still learning the basics 127 00:05:30.881 --> 00:05:33.380 and just want to make things work 128 00:05:33.380 --> 00:05:36.915 and of course have some fun along the way. 129 00:05:36.915 --> 00:05:39.351 So this was the hardest part 130 00:05:39.351 --> 00:05:41.164 I believe at least. 131 00:05:41.164 --> 00:05:42.523 Now all we have to do 132 00:05:42.523 --> 00:05:46.145 is to write this string here. 133 00:05:46.145 --> 00:05:48.450 Let me actually copy the example 134 00:05:48.450 --> 00:05:49.650 so we have it 135 00:05:49.650 --> 00:05:51.027 as a reference down here. 136 00:05:51.027 --> 00:05:54.543 Otherwise I'm gonna get a bit lost. 137 00:05:57.030 --> 00:06:00.591 So if mark.bmi 138 00:06:00.591 --> 00:06:04.600 is larger than john.bmi 139 00:06:05.891 --> 00:06:09.303 then console.log. 140 00:06:10.987 --> 00:06:15.987 So let's get the full name now from the object. 141 00:06:16.590 --> 00:06:17.590 So mark.fullNameBMI. 142 00:06:21.120 --> 00:06:22.890 And now we also 143 00:06:22.890 --> 00:06:25.350 need it here in these parenthesis. 144 00:06:25.350 --> 00:06:26.910 So let's put it there. 145 00:06:26.910 --> 00:06:28.690 mark.bmi 146 00:06:30.150 --> 00:06:30.983 is 147 00:06:32.130 --> 00:06:33.610 higher than 148 00:06:34.500 --> 00:06:36.783 and now let me just copy it here. 149 00:06:40.260 --> 00:06:41.580 So 150 00:06:41.580 --> 00:06:43.290 and again I'm using command D 151 00:06:43.290 --> 00:06:45.480 to select the next occurrence. 152 00:06:45.480 --> 00:06:48.990 And then let's just replace it with John. 153 00:06:48.990 --> 00:06:52.743 So Mark's BMI is higher than John's bmi. 154 00:06:54.570 --> 00:06:56.553 And now let's grab this again. 155 00:06:57.450 --> 00:06:59.350 Else if 156 00:07:01.110 --> 00:07:02.710 john.bmi 157 00:07:03.984 --> 00:07:04.817 is larger than 158 00:07:06.499 --> 00:07:07.600 mark.bmi 159 00:07:08.640 --> 00:07:11.163 then essentially say the opposite. 160 00:07:12.030 --> 00:07:13.953 So here it's gonna be John, 161 00:07:16.170 --> 00:07:17.003 and again 162 00:07:17.003 --> 00:07:17.836 command D 163 00:07:18.870 --> 00:07:21.840 and here, it's gonna be Mark. 164 00:07:21.840 --> 00:07:22.863 Okay, 165 00:07:25.410 --> 00:07:28.230 so 27 is higher than 24 166 00:07:28.230 --> 00:07:31.860 and that 27 belongs to Mark. 167 00:07:31.860 --> 00:07:35.940 And so this seems to be about right 168 00:07:35.940 --> 00:07:37.830 but it's not completely right. 169 00:07:37.830 --> 00:07:39.150 So ah, 170 00:07:39.150 --> 00:07:42.120 of course here it should be lowercase. 171 00:07:42.120 --> 00:07:43.830 So bmi. 172 00:07:43.830 --> 00:07:46.500 And now I cannot use the command D 173 00:07:46.500 --> 00:07:49.530 because then it will select this one as well. 174 00:07:49.530 --> 00:07:51.690 So I'm double clicking on this one 175 00:07:51.690 --> 00:07:54.510 and I hope that you're finding these vs code tips 176 00:07:54.510 --> 00:07:56.610 useful as well. 177 00:07:56.610 --> 00:07:57.780 So I'm clicking 178 00:07:57.780 --> 00:08:00.690 or actually I'm double clicking on this one 179 00:08:00.690 --> 00:08:03.330 then I hold down the command key, 180 00:08:03.330 --> 00:08:04.920 which in your case might be 181 00:08:04.920 --> 00:08:07.770 the control key or maybe the option key. 182 00:08:07.770 --> 00:08:09.570 So I know there are different configurations 183 00:08:09.570 --> 00:08:10.680 for this 184 00:08:10.680 --> 00:08:12.570 and it might not even work for you 185 00:08:12.570 --> 00:08:14.910 so please don't ask 186 00:08:14.910 --> 00:08:16.740 any question in that case. 187 00:08:16.740 --> 00:08:17.573 But for me 188 00:08:17.573 --> 00:08:19.200 I just have to hit command 189 00:08:19.200 --> 00:08:20.490 and then I can double click 190 00:08:20.490 --> 00:08:24.660 on multiple words and then all of them get selected. 191 00:08:24.660 --> 00:08:27.030 So now I have these four multiple cursors here 192 00:08:27.030 --> 00:08:27.960 again 193 00:08:27.960 --> 00:08:29.874 and I can simply delete all of them 194 00:08:29.874 --> 00:08:31.327 and write 195 00:08:31.327 --> 00:08:34.010 the one that I'm interested in. 196 00:08:34.010 --> 00:08:36.715 So that's the lowercase bmi 197 00:08:36.715 --> 00:08:39.832 and now we get the correct values 198 00:08:39.832 --> 00:08:41.586 and also this 199 00:08:41.586 --> 00:08:43.162 conditional logic 200 00:08:43.162 --> 00:08:45.487 is correct as well. 201 00:08:45.487 --> 00:08:46.620 And so with this, 202 00:08:46.620 --> 00:08:49.205 we did actually solve the challenge. 203 00:08:49.205 --> 00:08:51.903 And with this we also finished this introduction 204 00:08:51.903 --> 00:08:54.630 to JavaScript objects. 205 00:08:54.630 --> 00:08:55.620 And once again, 206 00:08:55.620 --> 00:08:57.870 I really want to congratulate you 207 00:08:57.870 --> 00:09:00.281 for the progress that you are making here. 208 00:09:00.281 --> 00:09:03.330 Great job and really well done. 209 00:09:03.330 --> 00:09:04.470 And I really mean it 210 00:09:04.470 --> 00:09:06.600 because I know how hard it is 211 00:09:06.600 --> 00:09:08.040 to stick to a course 212 00:09:08.040 --> 00:09:10.164 like this and to learn a completely 213 00:09:10.164 --> 00:09:13.081 new thing that is probably a bit confusing 214 00:09:13.081 --> 00:09:15.168 for you at this point still. 215 00:09:15.168 --> 00:09:16.503 Just keep in mind 216 00:09:16.503 --> 00:09:19.929 that that is absolutely no problem at all. 217 00:09:19.929 --> 00:09:22.830 And actually in the next section 218 00:09:22.830 --> 00:09:24.420 I believe I have a video 219 00:09:24.420 --> 00:09:25.637 about how to learn, 220 00:09:25.637 --> 00:09:27.701 how to learn basically. 221 00:09:27.701 --> 00:09:29.677 So about learning how to code 222 00:09:29.677 --> 00:09:31.201 and there's a lot of great tips 223 00:09:31.201 --> 00:09:32.568 that I'm sharing there. 224 00:09:32.568 --> 00:09:33.906 So once you reach that, 225 00:09:33.906 --> 00:09:36.112 make sure to watch it carefully. 226 00:09:36.112 --> 00:09:37.563 But now anyway, 227 00:09:37.563 --> 00:09:39.926 I will leave you to review this lecture 228 00:09:39.926 --> 00:09:40.759 if you want 229 00:09:40.759 --> 00:09:42.591 or to move on together with me 230 00:09:42.591 --> 00:09:45.510 to the next video where we are now 231 00:09:45.510 --> 00:09:48.063 gonna start talking about loops.