Intro to TypeScript

Intro to TypeScript for WWCode's May JS Study Night

Preparation

In order to work with TypeScript, please install the following: Node: I recommend installing via HomeBrew. To do that, run the following commands:

• Homebrew: ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
• Node: brew install node
• Verify by running node -v. NPM: This should come with your Node installation. Verify by running npm -v. VS Code: (recommended) Download Here

Install TypeScript

Before we start coding, we need to install TypeScript. Open the terminal and type the following command:

npm install -g typescript

Verify it's installed by running the command tsc -v. This will display the version of the TypeScript installed.

The TypeScript Compiler

Next, we're going to learn how to start using TypeScript compilation and write a TypeScript configuration file.

Navigate into the exercises/1-intro-to-compiling folder.

Run tsc src/index.ts. See the errors in your console? Run tsc src/index.ts --target ES2015 or tsc src/index.ts --target ES2017. Look at how the code has changed.

Now let's try running a TypeScript file with node. Try node src/index.ts. Run tsc src/index.ts --target ES2017 --module commonjs. Looks like it compiled without issues; try running node src/index.js, rather than .ts.

Examine the tsconfig. Now run tsc. Go into the newly created lib folder and look at the index.js file.

Learn more about tsconfigs here: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html

Exercises: Code Sandbox

Use the code sandbox links here to run the exercises: https://codesandbox.io/s/l74z601pj9

BONUS: Run the exercises locally, using your own tsconfig.