System Design Quiz Practice

class TokenBucket {
  constructor({ capacity, refillRatePerSecond }) {
    this.capacity = capacity; this.tokens = capacity;
    this.refillRatePerSecond = refillRatePerSecond; this.lastRefill = Date.now();
  }
  _refill() {
    const now = Date.now();
    const elapsed = (now - this.lastRefill) / 1000;
    this.tokens = Math.min(this.capacity, this.tokens + elapsed * this.refillRatePerSecond);
    this.lastRefill = now;
  }
  tryConsume(n = 1) {
    this._refill();
    if (this.tokens >= n) { this.tokens -= n; return true; }
    return false;
  }
}
const b = new TokenBucket({ capacity: 5, refillRatePerSecond: 0 });
for (let i = 0; i < 5; i++) console.log(b.tryConsume());
console.log(b.tryConsume());