Node.js Tutorial for Beginners - 12 - Core Modules Video Lecture -

alright guys so now that we know how to
write our own custom modules and we're a
little bit more familiar with them what
I want to do now is I want to start
talking to you about core modules now
these modules are a little bit different
because we don't write them ourselves
these core modules are the modules that
are already built in to node Jas
so of course node already comes with a
bunch of functionality that you're going
to be using a lot and well let's just go
ahead and get started first of all I
want to say that there are a ton of core
modules if I just take a couple
tutorials and try to explain them all
then it's going to be like eight days
long so instead of just going through
all of the core modules one by one I'm
going to be explaining them to you as we
need them in future programs but for
right now I'll show you guys like one or
two just do a you know just to
demonstrate them and by the way the
common practice is this well let me just
go ahead and show you guys a quick one
FS this is the file system module now
the first thing I want to point out is
again whenever you're making your own
custom modules you include the path
forward slash whenever using core
modules do not include the path at all
just the name of the module that way
note is aware of the fact that you know
what this is a core module not one that
you made yourself and it can find out a
lot faster the other thing you notice
and you probably noticed before it's
common practice to name the object or
the variable the same as the module and
this just clears up any confusion so
again what this is real quick example
this is the filesystem module and it
just allows you to pretty much read and
write files and also delete them so
let's say that we want to create a new
text file you can call FS write file
sync and as you saw I took three
parameters path which is pretty much the
name of the file so I just create one or
real quick and then like a text file
named corn the data is of course what
you know text you want inside the file
so I'll just put like
corn is good corn is life and we also
have an optional third parameter too but
we don't really need it so again
whenever I run this what it's going to
do and actually before I do that look in
here so it's going to create a corn text
document in the same directory so right
now I only have one file in here fjs
going to run this finished and check it
out we now have another one if we double
click it we can see corn is good corn is
life so that's what that does and of
course one other bit of code I'll show
you guys real quick is how to read files
so FS read file sync and you might
expect we'll just read that file that we
just created so what this does is it
pretty much reads it in and if we want
to convert it to a string then we just
call two string and since we're logging
it out it will display in the little
terminal so let me run this the file is
created and then it reads it and logs it
out so again that's just a quick little
demo of what a core module is again we
didn't write any of the code to write or
read files this is all built in node.js
for us so let me delete this and also
let me delete this corn crap all right
now just to show you guys one more arm
I'll show you guys the path module
equals choir path so the path module is
really good whenever you want to work
with on file paths so let me just go
ahead and write to quick file path I'll
put like uhm website home and we'll say
that this is some file on our desktop
arm in the directory called Bucky
I'm going to add a double slash here and
as you can see that's obviously not
something that you want and I'm going to
show you guys how we can fix that using
the path module but I'll just say like
the New Boston / index.html we'll say
that it's like a website or something
let me add a one more bag websites about
and this one will be just like abouts
that HTML with a single file alright so
what the path module is like I said is
it's really good whenever you want to
work with pass because one thing that
does is it normalizes your slashes in
other words if you guys ever notice um
different file paths on different
operating systems they either use a
backslash or a forward slash and what
half module can do is they can actually
normalize it depending on your operating
system so if you put like console.log
and useful like I don't know path
normalized we can do here is you can
just throw in a path and check out what
it does
so again actually as you can see right
here since I'm on Windows the slashes
are back slashes so anytime you have a
path as you can see I wrote a forward
slash right there it would convert them
all into back slashes and another thing
that it does is this you see yeah we
were using Rio and art you see how after
Bucky I accidentally put two forward
slashes well it knows you know what
that's obviously not what you wanted
that was probably a typo so it converts
it to one so you're going to use this a
lot whenever you're working with um web
servers and I'll show you guys how to
create an HTTP server and a file server
in the upcoming tutorials but for now I
just wanted to do a you know show you
guys and I'll show you guys a couple of
other cool things around here so
let me just log three different things
out real quick all right so another cool
thing that you're going to want to use
is this path dot Durer named der named
art website about and might as well just
write Amaro real quick so f dot base
name web site about and path the
extension name web site about art so you
see whenever you have a file path it's
kind of broken up into a couple
different pieces you have the main path
the main location of it you also have
the file itself which is pretty much the
core file just this in every single file
on your computer has an extension is a
text file is it an HTML file is a JPEG
whatever so using these functions on the
path module what we can do is we can
actually rip out the pieces of
information that we need
so again dirt name as you can see it
pretty much gives you the name of the
directory or the path without the file
portion of it base name what this does
is it just looks at the base or in other
words the file name and the extension
it just looks what type of file it is in
other words the file extension so again
those are three other cool things that
we're going to be using a lot so there
you go that's pretty much how you work
with core modules pretty much modules
that are already built in to note and
since I have some extra time what I want
to do is this I'm going to show you guys
like three other quick things these
really don't have anything to do with
core modules directly but like I said in
the next tutorial I'm going to be
showing you guys how to create like a
simple HTTP server and file server so I
just want to explain these because I'm
going to be using them in the future so
you know before we had a function called
set timeout and we already know what
that did you're pretty much scheduled a
little bit of code or a callback method
to run after a certain period of time
well we also have this thing called set
interval and it's kind of similar
actually what we can do in here is we
can have a bit of code to run actually
let me actually show you guys alright so
just like before we can have some
function in here and it's just going to
like log out the word beef and we can
have make sure it's a great place and we
can have this run like every two seconds
so you may be looking at this and you're
like alright is this like the exact same
method is set time out because it looks
really similar well the difference
between set interval and set timeout as
set timeout runs once after the period
of time set interval runs repeatedly so
every two seconds any code that's in the
callback is going to be called so every
two seconds as you can see beef is being
called so again that's just one little
quick thing that I wanted to mention and
before I let you guys go I want to
explain this so actually let me just log
this out it's let me know I got two
different things
all right so another little bit of code
that we're going to be working with a
lot is der name and also file name now
this is kind of similar to what I was
showing you with a path module but
essentially what this is going to do is
it's going to give you the directory
name in other words the full path and
also the file name which is the full
path plus the file plus the extension of
whatever file is currently calling this
code so again since it's fjs it's giving
us this for app j s and I know that
these are kind of random things that I'm
teaching guys but first of all you know
I didn't want to like spend a tutorial
teaching you guys like two lines of code
and also like I said they're going to
come in handy in the next couple
tutorials so you guys will thank me then
so anyways there you go
thank you guys for watching I'll see you
next time