It's just JavaScript
Here's some TypeScript code:
const array = [1, 2, 3, 4, 5]
function squareNumber(num) {
return num * num
}
const squared = array.map(squareNumber)
squared // [1, 4, 9, 16, 25]
array // [1, 2, 3, 4, 5]
const doubled = array.map(num => num * 2); // [2, 4, 6, 8, 10]
const books = [
{
name: "JavaScript: The Definitive Guide",
description: `Since 1996, JavaScript: The Definitive Guide...`,
price: 28.89
},
{
name: "Eloquent JavaScript",
description: `JavaScript lies at the heart...`,
price: 21.22
},
{
name: "JavaScript: The Good Parts",
description: `Most programming languages...`,
price: 16.59
}
];
const getTitle = book => book.name;
const titles = books.map(getTitle);
const titlesOfExpensiveBooks = books
.filter(book => book.pirce > 20)
.map(getTitle);
What's the point then? Let's take a look.

Benefits of TypeScript

  • type safety
  • your editor gets smarter
  • no need for as many unit tests as you need now
  • almost no entry cost if you already know JS
  • most (?) of the latest JS features

By the way

During this workshop we'll be using the latest version of TypeScript (3.6.3) that has been installed with create-react-app on project creation.
If you haven't created a project yet, now's the last chance, here's what to do:
npx create-react-app react-ts-devmeeting --typescript
cd react-ts-devmeeting && npm start

Resources