WEBVTT 00:01.110 --> 00:06.690 In this video, I'm going to show you one more distinction between objects and primitives, in some 00:06.690 --> 00:08.410 ways their behavior is different. 00:09.390 --> 00:13.000 Let's suppose that we have a variable AI which has the value ten. 00:13.740 --> 00:20.790 So when the variable AI is created, JavaScript engine in memory creates new spot for this variable 00:21.330 --> 00:23.640 and saves the value of a certain. 00:25.220 --> 00:32.630 Then again, suppose that we have variable B, which equals to eight, in this case, JavaScript engine 00:32.630 --> 00:39.740 creates different spot in memory for variable B and copies the value of A, which is 10. 00:41.060 --> 00:48.110 So you see that we have two different variables, A and B in memory, we have two different spots for 00:48.110 --> 00:50.980 them and both variables have the same value. 00:52.640 --> 01:00.560 After that, if we change the value of variable A and assigned to it 20, then it will change its value 01:00.560 --> 01:01.340 into twenty. 01:01.490 --> 01:08.330 But the variable B will remain its value as ten makes sense, right? 01:09.650 --> 01:10.570 It's not special. 01:10.880 --> 01:12.170 I think it's obvious. 01:13.520 --> 01:16.430 But something different happens when we deal with objects. 01:17.420 --> 01:21.730 Let's say we have objects C which has property name with value, John. 01:22.400 --> 01:30.320 So when this object is created, javascript engine in memory creates new memory space for it and variable 01:30.320 --> 01:32.830 C is just a reference for this object. 01:33.590 --> 01:38.090 It means that variable C knows where the object is located in memory. 01:39.250 --> 01:46.690 OK, let's suppose that we have a variable deal, which equals two variable C in this case for variable 01:46.690 --> 01:52.310 D, there is not created a new spot in memory space as it was in case of primitives. 01:52.960 --> 02:00.300 The fact is that the variable D as variable C becomes just one more reference to the existing object. 02:01.570 --> 02:03.510 So it's something different, right. 02:04.030 --> 02:11.350 In case of primitives, variables copied the values, but in case of objects, variable D did not copy 02:11.350 --> 02:16.300 the value of verbal C, it just became the reference for the existing object. 02:17.850 --> 02:24.960 Of course, if we change the value of name property, John will be replaced with Nick and if we check 02:24.960 --> 02:29.490 values of nine properties for ACMD, it will be the exact same. 02:30.210 --> 02:32.190 We will get Nick in both cases. 02:33.930 --> 02:42.660 OK, let's open our text editor and recall the first example regarding primitives, so we had variable 02:42.660 --> 02:44.820 AI, which was equal to 10, so right. 02:44.820 --> 02:50.400 VA equals to ten and then VA p equals to a. 02:53.240 --> 02:59.780 Below, right, a equals 220, let's lock them in council, right, consultor like a. 03:02.050 --> 03:03.700 And then cancel that Lockerby. 03:06.460 --> 03:07.000 Remote. 03:08.370 --> 03:17.220 So he would have different values for A and B, 20 and 10, and if we check global window object right 03:17.220 --> 03:18.210 window don't castle. 03:20.390 --> 03:21.530 Then drop down it. 03:23.510 --> 03:29.030 You see that we have variable rate and variable B with different values. 03:29.720 --> 03:32.840 So again, they took different spots in memory. 03:33.230 --> 03:39.050 And because of that, when we change the value of a it didn't have an effect on the value of variable 03:39.050 --> 03:39.290 B. 03:40.740 --> 03:44.970 OK, now let's create object right for sequel's. 03:46.140 --> 03:49.440 The right name, property and the value, John. 03:51.380 --> 03:54.590 Below right variable D equals to C. 03:58.190 --> 04:01.670 Reload and then check again, window object. 04:06.050 --> 04:12.620 So you see that we have here variable C and below, we have variable as well. 04:13.490 --> 04:17.110 They have the same values for name property, which is John. 04:18.620 --> 04:21.500 It seems that they look like as different objects. 04:21.500 --> 04:22.940 But actually it's not right. 04:23.570 --> 04:29.090 In order to prove that I'm going to change the value of object C or D doesn't matter. 04:29.510 --> 04:30.190 That's right. 04:30.200 --> 04:33.530 C dot name equals unique. 04:36.830 --> 04:39.600 Then reload and check again. 04:39.620 --> 04:41.390 We don't object right window. 04:43.400 --> 04:44.660 And dropped down eight. 04:47.550 --> 04:54.230 You see that both of them have changed the values in Tenwick, it means that they are not different. 04:54.660 --> 05:00.300 We have just one object in memory and see and they are just references of that object. 05:01.680 --> 05:02.300 Makes sense. 05:03.690 --> 05:11.160 All right, let's try something different instead of documentation, let's use equal sign to change 05:11.160 --> 05:12.510 the value of any property. 05:12.600 --> 05:14.160 So write sequels. 05:16.460 --> 05:17.840 And write your name. 05:19.480 --> 05:20.290 Disvalue, Bob. 05:23.520 --> 05:24.120 Reload. 05:25.860 --> 05:27.270 And right again, rindo. 05:31.350 --> 05:40.720 So you see that variable C has the value of name property as Bob and Variable D still has value as Nick. 05:41.580 --> 05:49.470 It means that when we used equals sine we have created a new object which to different spot in memory. 05:50.700 --> 05:53.760 OK, let's see exactly what happened. 05:54.480 --> 06:01.500 So when the C variable was created, JavaScript Engine created a new spot in memory for that object. 06:02.540 --> 06:09.690 Then we had a variable D which was equal to C and they both were references for the same object. 06:11.200 --> 06:18.760 Then using dot operator, we have changed the value of name property in Tenwick, so nothing special 06:18.760 --> 06:19.150 happened. 06:19.570 --> 06:28.660 CI a. still referenced to the same object, but when we used equal sign and changed the name into that 06:28.660 --> 06:33.190 new object was created which took new spot in memory space. 06:33.850 --> 06:40.930 So D was remained as a reference for a previous object and C became a reference for newly created object. 06:42.170 --> 06:45.530 That's why didn't it change the content of the. 06:48.220 --> 06:55.840 All right, that's the way how objects and primitives act, I think it was interesting and clear for 06:55.840 --> 06:56.040 you. 06:56.650 --> 06:57.820 See you in the next video.