one/dist/esm/link/prefetchViewport.test.native.js

One is a new React Framework that makes Vite serve both native and web.

import { describe, expect, it, beforeEach, vi } from "vitest";
import { createPrefetchViewport } from "./prefetchViewport.native.js";
function _class_call_check(instance, Constructor) {
  if (!(instance instanceof Constructor)) {
    throw new TypeError("Cannot call a class as a function");
  }
}
function _defineProperties(target, props) {
  for (var i = 0; i < props.length; i++) {
    var descriptor = props[i];
    descriptor.enumerable = descriptor.enumerable || false;
    descriptor.configurable = true;
    if ("value" in descriptor) descriptor.writable = true;
    Object.defineProperty(target, descriptor.key, descriptor);
  }
}
function _create_class(Constructor, protoProps, staticProps) {
  if (protoProps) _defineProperties(Constructor.prototype, protoProps);
  if (staticProps) _defineProperties(Constructor, staticProps);
  return Constructor;
}
var mockIOCallback;
var mockObserved = /* @__PURE__ */new Set();
vi.stubGlobal("IntersectionObserver", /* @__PURE__ */function () {
  "use strict";

  function _class(callback) {
    _class_call_check(this, _class);
    mockIOCallback = callback;
  }
  _create_class(_class, [{
    key: "observe",
    value: function observe(el) {
      mockObserved.add(el);
    }
  }, {
    key: "unobserve",
    value: function unobserve(el) {
      mockObserved.delete(el);
    }
  }, {
    key: "disconnect",
    value: function disconnect() {
      mockObserved.clear();
    }
  }]);
  return _class;
}());
function simulateIntersect(el, isIntersecting) {
  mockIOCallback([{
    target: el,
    isIntersecting
  }], {});
}
describe("prefetchViewport", function () {
  var prefetched;
  var vp;
  beforeEach(function () {
    prefetched = [];
    mockObserved.clear();
    vp = createPrefetchViewport();
    vp.start(function (href) {
      return prefetched.push(href);
    });
  });
  it("prefetches when link enters viewport", function () {
    var el = {};
    vp.observe(el, "/about");
    simulateIntersect(el, true);
    expect(prefetched).toEqual(["/about"]);
  });
  it("does not prefetch when link exits viewport", function () {
    var el = {};
    vp.observe(el, "/about");
    simulateIntersect(el, false);
    expect(prefetched).toEqual([]);
  });
  it("only prefetches each href once", function () {
    var el = {};
    vp.observe(el, "/about");
    simulateIntersect(el, true);
    simulateIntersect(el, false);
    simulateIntersect(el, true);
    expect(prefetched).toEqual(["/about"]);
  });
  it("cleanup re-enables prefetch for href", function () {
    var el = {};
    var cleanup = vp.observe(el, "/about");
    simulateIntersect(el, true);
    expect(prefetched).toEqual(["/about"]);
    cleanup();
    prefetched.length = 0;
    vp.observe(el, "/about");
    simulateIntersect(el, true);
    expect(prefetched).toEqual(["/about"]);
  });
  describe("memory and performance", function () {
    it("does not leak elements after cleanup", function () {
      var elements = [];
      var cleanups = [];
      for (var i = 0; i < 100; i++) {
        var el = {};
        elements.push(el);
        cleanups.push(vp.observe(el, `/page-${i}`));
      }
      expect(vp.nodes.size).toBe(100);
      cleanups.forEach(function (c) {
        return c();
      });
      expect(vp.nodes.size).toBe(0);
      expect(vp.done.size).toBe(0);
    });
    it("handles rapid observe/unobserve cycles", function () {
      var el = {};
      for (var i = 0; i < 100; i++) {
        var cleanup = vp.observe(el, "/test");
        cleanup();
      }
      expect(vp.nodes.size).toBe(0);
    });
  });
});
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