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The TypeScript programming language is a superset of JavaScript that adds types to JavaScript using a set of tools called a type system.

Lesson 1 of 1
  1. 1
    Invented in 1995, JavaScript was designed as a small scripting language for simple web pages in browsers. It wasn’t until 1999 that JavaScript was capable of supporting the kinds of dynamic web pag…
  2. 2
    So now that we know why TypeScript exists, let’s talk about how we use it: + First, we write TypeScript code in files with the extension .ts. + Next, we run our code through the TypeScript […
  3. 3
    JavaScript allows us to assign any value to any variable. That makes it very flexible to use, which can be good for getting started quickly in coding. In practice, variables that are assigned value…
  4. 4
    Because TypeScript knows what types our objects are, it also knows what shapes our objects adhere to. An object’s shape describes, among other things, what properties and methods it does or do…
  5. 5
    There are some places where TypeScript will not try to infer what type something is—generally when a variable is declared without being assigned an initial value. In situations where it isn’t able …
  6. 6
    In some situations, we’d like to declare a variable without an initial value while still ensuring that it will only ever be assigned values of a certain type. If left as any, TypeScript won’t be ab…
  7. 7
    All right! You’ve taken some first steps into the wonderful world of type safety with TypeScript. 💪 To recap, you’ve learned: * TypeScript is a superset of JavaScript that adds types. * The _ty…

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