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HTML
<div id="infinite-scroll-container">
<div id="sentinel"></div>
<div class="item">A</div>
<div class="item">B</div>
<div class="item">C</div>
<div class="item">D</div>
<div class="item">E</div>
<button id="infinite-scroll-button" disabled>
<span class="disabled-text">Loading more items...</span>
<span class="active-text">Show more</span>
</button>
</div>
CSS
:root {
--active-button-primary: #0080ff;
--active-button-font:#ffffff;
--disabled-button-primary: #f5f5f5;
--disabled-button-secondary: #c4c4c4;
--disabled-button-font: #000000;
}
#infinite-scroll-container {
position: relative;
}
#sentinel {
position: absolute;
bottom: 150vh;
}
#infinite-scroll-button {
cursor: pointer;
border: none;
padding: 1em;
width: 100%;
font-size: 1em;
}
#infinite-scroll-button:enabled {
color: var(--active-button-font);
background-color: var(--active-button-primary)
}
#infinite-scroll-button:disabled {
color: var(--disabled-button-font);
background-color: var(--disabled-button-primary);
cursor: not-allowed;
animation: 3s ease-in-out infinite loadingAnimation;
}
#infinite-scroll-button:enabled .disabled-text {
display: none;
}
#infinite-scroll-button:disabled .active-text {
display: none;
}
@keyframes loadingAnimation {
0% {
background-color: var(--disabled-button-primary);
}
50% {
background-color: var(--disabled-button-secondary);
}
100% {
background-color: var(--disabled-button-primary);
}
}
JS
function infiniteScroll() {
let responseBuffer = [];
let hasMore;
let requestPending = false;
const loadingButtonEl = document.querySelector('#infinite-scroll-button');
const containerEl = document.querySelector('#infinite-scroll-container');
const sentinelEl = document.querySelector("#sentinel");
const insertNewItems = () => {
while (responseBuffer.length > 0) {
const data = responseBuffer.shift();
const el = document.createElement("div");
el.textContent = data;
el.classList.add("item");
el.classList.add("new");
containerEl.insertBefore(el, loadingButtonEl);
console.log(`inserted: ${data}`);
}
sentinelObserver.observe(sentinelEl);
if (hasMore === false) {
loadingButtonEl.style = "display: none";
sentinelObserver.unobserve(sentinelEl);
listObserver.unobserve(loadingButtonEl);
}
loadingButtonEl.disabled = true
}
loadingButtonEl.addEventListener("click", insertNewItems);
const requestHandler = () => {
if (requestPending) return;
console.log("making request");
requestPending = true;
fakeServer.fakeRequest().then((response) => {
console.log("server response", response);
requestPending = false;
responseBuffer = responseBuffer.concat(response.items);
hasMore = response.hasMore;
loadingButtonEl.disabled = false;;
});
}
const sentinelObserver = new IntersectionObserver((entries, observer) => {
entries.forEach(entry => {
if (entry.intersectionRatio > 0) {
observer.unobserve(sentinelEl);
requestHandler();
}
});
});
const listObserver = new IntersectionObserver((entries, observer) => {
entries.forEach(entry => {
if (entry.intersectionRatio > 0 && entry.intersectionRatio < 1) {
insertNewItems();
}
});
}, {
rootMargin: "0px 0px 200px 0px"
});
sentinelObserver.observe(sentinelEl);
listObserver.observe(loadingButtonEl);
}
infiniteScroll();
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2023-07-05 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2023-07-05 UTC."],[],[]]