Data Structures

TypeScript Generic Stack Data Structure

Implement a type-safe Last-In-First-Out (LIFO) Stack data structure in TypeScript with full generic parameterization and peek/pop protections.

TypeScript Source Code

Editable code sample with line numbers

TypeScript

interface IStack<T> {
  push(item: T): void;
  pop(): T | undefined;
  peek(): T | undefined;
  size(): number;
  isEmpty(): boolean;
  clear(): void;
}

class Stack<T> implements IStack<T> {
  private items: T[] = [];

constructor(initialItems?: T[]) {
    if (initialItems) {
      this.items = [...initialItems];
    }
  }

push(item: T): void {
    this.items.push(item);
  }

pop(): T | undefined {
    return this.items.pop();
  }

peek(): T | undefined {
    return this.items[this.items.length - 1];
  }

size(): number {
    return this.items.length;
  }

isEmpty(): boolean {
    return this.items.length === 0;
  }

clear(): void {
    this.items = [];
  }
}

// Example 1: Numeric Stack
const numStack = new Stack<number>();
numStack.push(10);
numStack.push(20);
numStack.push(30);

console.log("Top element:", numStack.peek()); // 30
console.log("Popped:", numStack.pop());       // 30
console.log("Stack size:", numStack.size());  // 2

// Example 2: Strongly-typed Object Stack
interface UserAction {
  id: string;
  action: string;
}

const actionHistory = new Stack<UserAction>();
actionHistory.push({ id: 'u1', action: 'CREATE_FILE' });
actionHistory.push({ id: 'u2', action: 'EDIT_CODE' });

console.log("Last action:", actionHistory.peek()?.action);

Expected Output

When this program is compiled and executed, the terminal outputs:

Top element: 30
Popped: 30
Stack size: 2
Last action: EDIT_CODE

How the Code Works

This TypeScript implementation demonstrates Generics (<T>), interfaces, and private access modifiers. The class Stack<T> enforces compile-time type safety so a Stack<number> cannot accept strings or incompatible types. Peek and pop methods safely return T | undefined to handle empty stack states without runtime crashes.

Time Complexity

O(1) for push, pop, and peek

Space Complexity

O(N) where N is number of stored elements

Key Takeaways & Best Practices

Generics (<T>) allow reusable data structures while maintaining strict compile-time types.
Private class fields (private items: T[]) prevent external callers from bypassing encapsulated rules.

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Runnable Code

View Code

How the Code Works

Time Complexity

O(1) for push, pop, and peek

Space Complexity

O(N) where N is number of stored elements

Key Takeaways & Best Practices

Generics (<T>) allow reusable data structures while maintaining strict compile-time types.
Private class fields (private items: T[]) prevent external callers from bypassing encapsulated rules.

TypeScript Generic Stack Data Structure

TypeScript Source Code

Expected Output

How the Code Works

Key Takeaways & Best Practices

Master TypeScript with ZenCompiler

Related TypeScript Examples

TypeScript LRU Cache Implementation

Python Program to Check Prime Number

Python Program for Fibonacci Series

Platform & Tools

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TypeScript Generic Stack Data Structure

TypeScript Source Code

Expected Output

How the Code Works

Key Takeaways & Best Practices

Master TypeScript with ZenCompiler

Related TypeScript Examples

TypeScript LRU Cache Implementation

Python Program to Check Prime Number

Python Program for Fibonacci Series