Skill Check

Areas I need to understand more deeply: §

• The JS event loop and call stack
• Higher order functions and their implementation
• React Router
• middleware (design patterns)
• Algorithms
• Leetcode fundamentals
• Mastering common data structures:
  • Set
  • Map/Reduce
  • Queues
  • LinkedLists
• Revision on how authentication works with JWT
• webSockets fundamentals
• React:
  • custom hooks (how to create them and use them)
  • useContext
  • useMemo
  • server actions
• Working with Classes in Javascript
  • constructor
  • this() function
  • can you understand this fully and why Solution Two is so much better?

// Solution One
class PriorityQueue {
    constructor() {
        this.items = [];
    }
 
    enqueue(item, priority) {
        this.items.push({ item, priority });
        this.items.sort((a, b) => a.priority - b.priority);
    }
 
    dequeue() {
        return this.items.shift().item;
    }
}
 
// Solution Two
class PriorityQueue {
    queues = new Map<number, any[]>()
        .set(0, [])
        .set(1, [])
        .set(2, []);
 
    queue(priority: number, item: any): PriorityQueue {
        this.queues.get(priority).push(item);
        return this;
    }
 
    dequeue(priority: number): any {
        const queue = this.queues.get(priority);
        const value = queue.shift();
        this.queues.set(priority, queue);
        return value;
    }
}