Writing generic code by using type parameters

In the beginning of the section on using static typing, we mentioned the type parameters. In order to get a better understanding of them, let's begin with an example. Let's suppose that we want to implement the classical data structure BinarySearchTree. Let's define its interface using a class without applying any method implementations:

class Node { 
  value: any; 
  left: Node; 
  right: Node; 
} 
 
class BinarySearchTree { 
  private root: Node; 
  insert(any: value): void { /* ... */ } 
  remove(any: value): void { /* ... */ } 
  exists(any: value): boolean { /* ... */ } 
  inorder(callback: {(value: any): void}): void { /* ... */ } 
} 

In the preceding snippet, we defined a class called Node. The instances of this class represent the individual nodes in our tree. Each node has a left and a right child node and a value of the type any; we use any in order to be able to store...