TypeScript introduces strong typing to JavaScript through a simple syntax, referred to by Anders Hejlsberg as syntactic sugar. This sugar is what assigns a type to a variable. This strong typing syntax, which is officially called type annotation, is used wherever a variable is used. In other words, we can use type annotation in a variable declaration, a function parameter, or to describe the return type of a function itself.
As we discussed in Chapter 1, TypeScript – Tools and Framework Options, there are many benefits to enforcing types in a development language. These include better error checking, the ability for an IDE to provide more intelligent code suggestions, and the ability to introduce object-oriented techniques into the coding experience.
The TypeScript language uses several basic types, such as number and boolean, and...
