Types in TypeScript

Working with TypeScript or any other coding language means working with data, and such data can represent different sorts of content that are called types. Types are used to represent the fact that such data can be a text string, an integer value, or an array of these value types, among others. We may have already met types in JavaScript since we have always worked implicitly with them. This also means that any given variable could assume (or return, in the case of functions) any value.

Sometimes, this leads to errors and exceptions in our code because of type collisions between what our code returned and what we expected it to return type-wise. We can enforce this flexibility using a specific type called any, as we will see later in this chapter. However, statically typing our variables gives our IDE and us a good picture of what kind of data we are supposed to find in each instance of code. It becomes an invaluable way to help debug our applications at compile time before the code is executed.

The string type

One of the most widely used primitive types is the string, which populates a variable with a piece of text: