react-transition-preset/dist/viewport/index.js

Lightweight, zero-dependency transition component for React with common preset transition

// src/viewport/index.ts
var thresholds = {
  some: 0,
  all: 1
};
function resolveElements(elements) {
  if (typeof elements === "string") {
    elements = document.querySelectorAll(elements);
  } else if (elements instanceof Element) {
    elements = [elements];
  }
  return Array.from(elements || []);
}
function inView(elementOrSelector, onStart, { root, margin: rootMargin, amount = "some" } = {}) {
  const elements = resolveElements(elementOrSelector);
  const activeIntersections = /* @__PURE__ */ new WeakMap();
  const onIntersectionChange = (entries) => {
    entries.forEach((entry) => {
      const onEnd = activeIntersections.get(entry.target);
      if (entry.isIntersecting === Boolean(onEnd)) return;
      if (entry.isIntersecting) {
        const newOnEnd = onStart(entry);
        if (typeof newOnEnd === "function") {
          activeIntersections.set(entry.target, newOnEnd);
        } else {
          observer.unobserve(entry.target);
        }
      } else if (onEnd) {
        onEnd(entry);
        activeIntersections.delete(entry.target);
      }
    });
  };
  const observer = new IntersectionObserver(onIntersectionChange, {
    root,
    rootMargin,
    threshold: typeof amount === "number" ? amount : thresholds[amount]
  });
  elements.forEach((element) => observer.observe(element));
  return () => observer.disconnect();
}

export { inView, resolveElements };