Understanding the abstract syntax tree (AST)

As we have already learned, an abstract syntax tree, or AST, is a tree-like data structure used to represent the abstract syntactic structure of source code written in a programming language. Each node of the AST represents a construct that occurs in the source code.

We are now going to look at a small TypeScript code snippet to understand the AST in detail. There is nothing very special about the following code snippet—it simply declares an interface named Weapon and a couple of classes, named Katana and Ninja. It then creates an instance of the Ninja class and invokes one of its methods:

interface Weapon { 
    tryHit(fromDistance: number): boolean; 
} 
 
class Katana implements Weapon { 
    public tryHit(fromDistance: number) { 
        return fromDistance <= 2; 
    } 
} 
 
class Ninja { 
    private _weapon: Weapon;...