1 00:00:00,150 --> 00:00:01,460 Now in the last lecture, 2 00:00:01,460 --> 00:00:04,420 I talked about these levels of abstraction. 3 00:00:04,420 --> 00:00:08,620 And maybe it's already clear, at least to a certain extent, 4 00:00:08,620 --> 00:00:12,390 how exactly that's all meant to work and how that helps you. 5 00:00:12,390 --> 00:00:14,470 But it can also be intimidating. 6 00:00:14,470 --> 00:00:17,930 You might not be sure whether you can always determine 7 00:00:17,930 --> 00:00:21,540 if there are mixed levels of abstraction or not. 8 00:00:21,540 --> 00:00:23,420 Now that's no problem though. 9 00:00:23,420 --> 00:00:26,370 Of course, for one, that is also something 10 00:00:26,370 --> 00:00:28,160 that comes with experience, 11 00:00:28,160 --> 00:00:30,630 and it already is a good first step 12 00:00:30,630 --> 00:00:32,480 if you think about your code 13 00:00:32,480 --> 00:00:34,670 and you at least consider splitting it, 14 00:00:34,670 --> 00:00:37,210 even if you then make the wrong decision. 15 00:00:37,210 --> 00:00:39,870 I mean, what is the wrong decision anyways? 16 00:00:39,870 --> 00:00:42,420 It's your code and you are trying your best 17 00:00:42,420 --> 00:00:45,260 to make it as readable as possible. 18 00:00:45,260 --> 00:00:48,860 But in addition, I also got a rule of thumb for you, 19 00:00:48,860 --> 00:00:51,490 or actually two rules of thumb, 20 00:00:51,490 --> 00:00:55,630 which help you decide whether to split your code or not. 21 00:00:55,630 --> 00:00:57,930 You wanna split a function, 22 00:00:57,930 --> 00:01:00,720 or at least consider breaking up a function 23 00:01:00,720 --> 00:01:04,930 into multiple functions, if you can extract code, 24 00:01:04,930 --> 00:01:09,790 multiple lines of code, that work on the same functionality. 25 00:01:09,790 --> 00:01:12,870 For example, if you have a function which calls 26 00:01:12,870 --> 00:01:17,210 both setAge and setName, you could consider merging this 27 00:01:17,210 --> 00:01:20,100 into one function, a new function, 28 00:01:20,100 --> 00:01:22,120 or a new method in this case, 29 00:01:22,120 --> 00:01:24,580 which you outsource from that function 30 00:01:24,580 --> 00:01:26,800 in which it was originally. 31 00:01:26,800 --> 00:01:28,870 So that in your original function, 32 00:01:28,870 --> 00:01:32,430 you now only have to call one other function, 33 00:01:32,430 --> 00:01:34,280 which then does the actual work 34 00:01:34,280 --> 00:01:36,890 of setting an age and a name. 35 00:01:36,890 --> 00:01:39,500 So whenever you have an opportunity like this 36 00:01:39,500 --> 00:01:42,900 to remove a block of code from one function 37 00:01:42,900 --> 00:01:45,020 and put it into another function, 38 00:01:45,020 --> 00:01:46,653 you could consider doing that. 39 00:01:47,810 --> 00:01:51,260 The other rule of thumb which I have for you 40 00:01:51,260 --> 00:01:53,500 is that you want to extract code 41 00:01:53,500 --> 00:01:57,450 that requires more interpretation than the surrounding code. 42 00:01:57,450 --> 00:01:59,860 And that again is directly related 43 00:01:59,860 --> 00:02:02,240 to these levels of abstraction. 44 00:02:02,240 --> 00:02:05,290 If we have a look at this good old example here, 45 00:02:05,290 --> 00:02:09,380 then we can easily see that this email.includes check 46 00:02:09,380 --> 00:02:12,340 requires more interpretation from our side 47 00:02:12,340 --> 00:02:14,760 than having a look at saveNewUser. 48 00:02:14,760 --> 00:02:17,780 There it's directly obvious what this does 49 00:02:17,780 --> 00:02:18,910 and why we're doing this. 50 00:02:18,910 --> 00:02:22,480 For email.includes, we have to add the extra meaning 51 00:02:22,480 --> 00:02:25,530 of email validation being done here. 52 00:02:25,530 --> 00:02:28,930 So changing it to this code would bring it all back 53 00:02:28,930 --> 00:02:33,250 onto the same level of abstraction and on the same level 54 00:02:33,250 --> 00:02:36,150 of required interpretation, you could say. 55 00:02:36,150 --> 00:02:38,720 Because now we can easily read this code 56 00:02:38,720 --> 00:02:42,580 and the interpretation is all baked into the names. 57 00:02:42,580 --> 00:02:45,560 So you can also just have a look at these rules 58 00:02:45,560 --> 00:02:49,033 when it comes to deciding whether you wanna split or not.