WEBVTT 00:00.060 --> 00:00.510 OK. 00:00.840 --> 00:04.710 So it's time for a five minute crash course of note and Javascript. 00:04.710 --> 00:07.770 Obviously that's not enough time to even scratch the surface. 00:07.770 --> 00:12.940 But I'm just going to show you the basics of what you need to know for us to continue on with the course. 00:13.200 --> 00:13.770 OK. 00:13.950 --> 00:17.370 So back over in cloud 9 we will delete everything. 00:17.400 --> 00:19.660 Get rid of it so you can do that either. 00:19.670 --> 00:26.600 If you want to use a command line you can do use Ahram and armed dash R.F. or just highlight what you 00:26.600 --> 00:28.350 need to delete right quick. 00:28.400 --> 00:30.330 And where's that. 00:30.680 --> 00:36.260 And then we'll say yes to all you want to remove all of it and Humphrey now can get rid of some of this 00:36.260 --> 00:37.610 stuff. 00:37.610 --> 00:38.720 Perfect. 00:39.050 --> 00:40.180 Make some space. 00:40.190 --> 00:41.860 I'll bring this up a bit. 00:41.930 --> 00:47.660 Now all that we're going to do is make our first javascript file we can call it whatever we want. 00:47.720 --> 00:53.180 You can either use touch genius or what you know you don't have to call it app dodgiest where you can 00:53.180 --> 00:57.340 right click over here and click on new file. 00:57.380 --> 01:02.140 I'll do that one and I will call this oh I'll do it. 01:02.550 --> 01:04.090 It's a standard name. 01:04.570 --> 01:05.090 OK. 01:05.360 --> 01:07.220 And I won't recreate it down here. 01:07.220 --> 01:11.900 Now we'll open it up double quick and we'll add some javascript in here. 01:12.170 --> 01:17.570 So what I want to show you is this basic workflow with node that we kind of saw already we type some 01:17.650 --> 01:25.190 in a file we save it and then we execute the file with the command node space and then the name of the 01:25.190 --> 01:25.750 file. 01:26.000 --> 01:30.980 So it's very similar at least in principle to what we did with the sequel files where we had save a 01:30.980 --> 01:33.120 sequel file ending and as well. 01:33.350 --> 01:41.570 Put something in there a query then we would execute it using source and then some file name as well. 01:41.600 --> 01:43.150 Same idea. 01:43.520 --> 01:45.390 So I'm going to show you some very simple code. 01:45.410 --> 01:48.320 There's something called And again if you know this stuff. 01:48.320 --> 01:50.030 Feel free to skip it. 01:50.120 --> 01:55.220 Something called Constant Aag kind of the simplest possible commands you can do in my ask. 01:55.310 --> 01:56.720 It will just print something out. 01:56.900 --> 02:00.230 So we can do our basic hello. 02:00.440 --> 02:02.010 We don't need caps. 02:02.660 --> 02:03.760 Hello world. 02:05.780 --> 02:10.920 We'll put a semi-colon there which should seem familiar from my school at least. 02:10.920 --> 02:11.960 And let's start with this. 02:11.970 --> 02:18.870 Our first application very basic when all we need to do to execute is come down here and type node and 02:18.870 --> 02:27.780 the name of the file which we called app dot J.S. and it runs silly but it works OK. 02:27.870 --> 02:32.390 So that doesn't seem useful of course but it's something right. 02:32.550 --> 02:39.850 And to see kind of why a programming language would be useful let's at least do this 500 times. 02:40.110 --> 02:44.910 Maybe that's not useful but we can at least see how it's helpful at doing something that we can't do 02:44.910 --> 02:45.580 on our own. 02:45.900 --> 02:47.600 So we can create a simple loop 02:51.180 --> 02:54.710 will do less than five hundred. 02:54.780 --> 03:02.220 Now in my other courses this is like an entire video five or 10 minutes with exercises but not going 03:02.220 --> 03:03.360 to spend time on that. 03:03.360 --> 03:06.310 What this does is it says whatever's inside of here. 03:06.360 --> 03:07.880 Repeat 500 times. 03:08.190 --> 03:11.810 Basically this is a counter saying OK we're starting at zero. 03:11.880 --> 03:17.030 And every time through the loop we're going to add one to I which is what this does here. 03:17.250 --> 03:20.910 So we go 0 next time around 1 to 3. 03:21.000 --> 03:25.570 Keep going while it's less than five hundred as soon as it hits 500 we're done. 03:25.800 --> 03:26.180 OK. 03:26.280 --> 03:33.430 So if I just put that in there whatever's in these brackets here will happen 500 times. 03:33.540 --> 03:34.610 Let's do it now. 03:34.620 --> 03:40.170 One thing I could add that I probably should is this var key word it's just don't worry about it. 03:40.260 --> 03:43.190 But it's important to have it there. 03:43.290 --> 03:49.990 Now if I run it scroll up can see get hundreds of the world's Well 500. 03:50.010 --> 03:52.610 So imagine you might be wondering why you care. 03:52.740 --> 03:55.210 Well imagine instead of console log. 03:55.440 --> 03:59.470 What if we had insert a new user into the database. 03:59.790 --> 04:04.800 That would be a fantastic way to quickly see a database with a bunch of data. 04:04.800 --> 04:07.830 Remember how we had to do this obnoxious copy and paste. 04:07.860 --> 04:13.700 So I would give you a file you would copy and paste it like for the movies data and reviews areas these 04:13.710 --> 04:16.360 big files you have to copy and paste it in. 04:16.380 --> 04:18.970 It's an awful way of getting sampled data. 04:19.110 --> 04:21.990 Well we can use javascript to create data for us. 04:21.990 --> 04:24.120 So just a couple other things I'll show you. 04:24.320 --> 04:29.180 You know we can do math and basic things like five plus five. 04:29.640 --> 04:32.000 And I won't do this 500 times. 04:32.190 --> 04:35.970 We can comment things out selecting them and doing command slash. 04:35.970 --> 04:37.430 So that won't run anymore. 04:37.440 --> 04:39.900 So now I'm only running five plus five. 04:40.260 --> 04:41.670 You can see we get 10. 04:41.670 --> 04:45.920 One other thing to address is what what is node if you're not familiar with it. 04:45.970 --> 04:47.690 And that's actually a pretty common question. 04:47.700 --> 04:49.190 There's a bit of confusion about. 04:49.260 --> 04:50.190 No no. 04:50.220 --> 04:50.830 Yes. 04:50.880 --> 04:53.220 Which is what is called and regular Javascript. 04:53.220 --> 04:57.730 And what the difference is basically Javascript is a programming language was created first. 04:58.020 --> 05:03.010 It's been around for a while and it's existed as a language that you can use on the client side. 05:03.120 --> 05:10.190 So what that means is that back on this diagram there's a line right here not right now but imagine 05:10.190 --> 05:10.750 a line. 05:10.800 --> 05:17.040 This is the client side so I could write javascript code that did things over on someone like on my 05:17.040 --> 05:23.310 computer you could write code that would animate something or make a game or just add some pretty effects. 05:23.310 --> 05:25.610 That's not to say that it's not powerful. 05:25.680 --> 05:31.210 But traditionally it was used to decorate pages if you will and it had nothing to do with databases. 05:31.230 --> 05:32.660 It had nothing to do with servers. 05:32.850 --> 05:38.400 You would use another language over here like DHP and you would use javascript's on the client side 05:38.400 --> 05:46.170 of the front end but then node came around about five years ago now and what it is is an implementation 05:46.230 --> 05:51.600 of javascript written so that you can use it on the backend so that you can do things like this you 05:51.600 --> 05:58.060 can create a server with javascript instead of having to do it with Ruby or THP and you can talk to 05:58.060 --> 06:01.380 a database like any other server side language. 06:01.380 --> 06:09.240 So to summarize that node is javascript it uses basically the exact same syntax but you can use it on 06:09.240 --> 06:12.240 the backend which is what we'll be doing in this course.