-
Book Overview & Buying
-
Table Of Contents
-
Feedback & Rating
Mastering Node.js Web Development
By :
Now that you understand the relationship between TypeScript and JavaScript, it is time to describe the basic language features you will need to follow the examples in this book. This is not a comprehensive guide to either TypeScript or JavaScript, but it should be enough to get you started.
The let keyword is used to define variables, and the const keyword is used to define a constant value that will not change, as shown in Listing 3.15.
Listing 3.15: Defining variables and constants in the index.ts file in the primer folder
let condition = true;
let person = "Bob";
const age = 40;
The TypeScript compiler infers the type of each variable or constant from the value it is assigned and will generate an error if a value of a different type is assigned. Types can be specified explicitly, as shown in Listing 3.16.
Listing 3.16. Specifying types in the index.ts file...