aperonight/app/javascript/controllers/counter_controller.js

import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
  static values = {
    target: { type: Number, default: 0 },
    decimal: { type: Boolean, default: false },
    duration: { type: Number, default: 2000 }
  }

  connect() {
    this.observer = new IntersectionObserver((entries) => {
      entries.forEach(entry => {
        if (entry.isIntersecting) {
          this.animate()
          this.observer.unobserve(this.element)
        }
      })
    }, { threshold: 0.5 })

    this.observer.observe(this.element)
  }

  disconnect() {
    if (this.observer) {
      this.observer.disconnect()
    }
  }

  animate() {
    // Find the target element with data-target-value
    const targetElement = this.element.querySelector('.stat-number');
    if (!targetElement) return;

    // Get the target value
    this.targetValue = parseInt(targetElement.getAttribute('data-target-value'), 10) || this.targetValue;

    const startValue = 0;
    const startTime = performance.now();

    const updateCounter = (currentTime) => {
      const elapsedTime = currentTime - startTime;
      const progress = Math.min(elapsedTime / this.durationValue, 1);

      // Easing function for smooth animation
      const easeOutQuart = 1 - Math.pow(1 - progress, 4);

      let currentValue = startValue + (this.targetValue - startValue) * easeOutQuart;

      if (this.decimalValue && this.targetValue < 10) {
        currentValue = currentValue.toFixed(1);
      } else {
        currentValue = Math.floor(currentValue);
      }

      // Update only the text content of the target element
      targetElement.textContent = currentValue;

      if (progress < 1) {
        requestAnimationFrame(updateCounter);
      } else {
        const finalValue = this.decimalValue && this.targetValue < 10
          ? this.targetValue.toFixed(1)
          : this.targetValue;
        targetElement.textContent = finalValue;
      }
    }

    requestAnimationFrame(updateCounter);
  }
}