Transcript:
Alright! Hello everybody!
So, I wanted to show you how to install TypeScript on macOS.
So, first things first we’re going to open up whatever your favorite browser is, or whatever browser you have installed. Here I’m going to be using Safari.
We are going to head over to https://nodejs.org
Now, you’ll see a page like this. It’ll give you a couple of different download options and you can opt for either the LTS or the current release.
Either one of those works. I’m going to say go for the LTS version. That’s because that stands for long-term support, so this is the version that’s going to keep getting security updates and things like that.
That’s probably the one you want to go with.
If you want to be on the bleeding edge, and have the latest and greatest feel free to go with the other one, it will work just as well. For this video I’m going to go with 10.15.1.
Very likely if you’re watching this at any point in the future these version numbers are going to be different. Node.js does a lot of releases so, it’s totally okay if you’re on a later version than I am. Everything should work just as well.
Download it.
Alright, it has finished downloading, so I’m going to go to my Downloads folder and open it.
We’re just going to click through here.
We’ll hit continue.
We’ll hit continue again. It’ll prompt us to agree to the license, click agree.
It’ll take 60 megabtyes of space, that’s fine by me, hit Install.
Enter your account password at the authorization prompt and hit Install Software.
Give that a few moments. Alright, and Node.js has been installed! Hit Close.
We don’t need the installer any more, so just hit “Move to Trash” here.
So, how can we verify that things are working here?
Well, let’s go to the application search in the top-right corner of the screen and look for “Terminal”.
Here we’ve got our Terminal. The way we can test if Node.js is installed properly is to type:
node
and hit enter.
And this little angle bracket should appear.
And we can start entering JavaScript code here. So, two plus two is four. Let’s see, we could do a setTimeout. So in 5 seconds that should display something. There it is.
If you want to get out of here just hit CTRL+C. Twice.
And then you’re back on the normal Terminal prompt.
So, let’s install TypeScript.
In order to install TypeScript we’re going to use something called npm. If you’re unfamiliar with npm that stands for the node package manager and that’s how lots of different Node.js based libraries and programs are distributed, TypeScript among them.
So, how do we use npm to install it? Well, here in this Terminal we’re going to type:
sudo npm install --global typescript
And hit enter.
Enter our password. Give that a few moments to do its thing.
And you’ll see here it says added one package from one contributor in 6 seconds.
Now it’s very likely that you’ll see a different version number here. TypeScript also like Node.js releases fairly frequently. TypeScript is really good about backwards compatibility, so you shouldn’t have to worry about anything you see in this video or any later video being incompatible.
If you wanted to be on the exact version that I am going to show you, though, what you can do is go back to the Terminal and run:
sudo npm uninstall --global typescript
To get rid of what we just installed. And we’ll then run a command similar to what we did before:
sudo npm install --global typescript@3.3.3
When you add that @ sign and then the version number, it’s going to guarantee that that’s the version you’re going to install rather than whatever the latest is (which is the default).
There we go. We’ve got that working.
So now what I’m going to do is create a new folder on the desktop. We’re going to call it “test” and we’re just going to see if TypeScript is working. It’s installed but is it actually working?
Let’s open up “test”. We’re going navigate our Terminal to this new folder as well. You can do this by typing:
cd Desktop/test
Once you’ve done that we’re going to create a file named main.ts. All TypeScript files end in .ts.
You can do this by entering the comand:
touch main.ts
You’ll see the file appears in the folder.
Now let’s put something in this main.ts file for TypeScript to compile.
So, we’re going to open up TextEdit. If you have a particular text editor that you prefer, feel free to use it. TextEdit is all I’ve got on this particular machine at the moment. I’m going to go to File -> Open and find main.ts in the folder on my Desktop.
And then we’ll put in the simplest possible “Hello, World!” program and save it.
Now in order for TypeScript to compile our “Hello, World!” program it needs a configuration file.
We can create the default one by going back to our Terminal and running:
tsc --init
If we hit enter, it’s going to create that file for us. So, you can see this tsconfig.json file has been created.
Don’t worry too much about that file I will be creating a video explaining exactly what it is, why we use it, how to use it, what the different options inside it mean for now all we need to know is that we need it there and now we have it.
And to get TypeScript to compile our main.ts file, just run:
tsc
It will find all the TypeScript files in this folder and compile them. You see we now have a main.js file.
We run that main.js file through Node.js, and see we’ve got “Hello, world!”
Awesome! Exactly what we wanted.
So everything’s working. If you’re seeing the same thing, hey you’re good to go, you’ve got TypeScript installed.
There is one other thing I wanted to show you: You can have TypeScript watch for changes, rather than having to rerun it each time you change something.
So, what we’re going to do is do is go back to our Terminal and enter:
tsc --watch
See it gives us a little message “starting compilation in watch mode”.
And then I’m going to go back to our file and say “Hello World! Again!” and I’m going to save it. And you see that flashed a bit. It said “file change detected”, “0 errors”.
We’re going to open up another Terminal and do the same “cd Desktop/test” that we did before.
You can see if we run our main.js, hey it says “Hello World! Again!” just like we wanted.
One thing that’s really nice about this is that if you make a mistake, here I’m going to forget to have the closing parenthesis and semicolon, if we save this TypeScript is going to give us an error and say “hey! I expected a closing parenthesis here!”
So we can add that back in and save it and everything’s happy again.
Very cool! That’s it!
You’ve got TypeScript installed!
By the way if you’re interested in going deep into learning TypeScript I’ve got this TypeScript by Example course that I’m working on now.
You can head on over to https://typescriptbyexample.com
Scroll down to the bottom, and you can put in your email address to be notified when the course is released.
Also, stay tuned to this YouTube channel for future updates. Thank you so much for watching!