PureScript 语言中的图片懒加载：Intersection Observer API 封装实践
随着互联网的快速发展，网页加载速度成为用户体验的重要指标之一。图片懒加载技术作为一种优化网页性能的有效手段，能够显著提升页面加载速度，减少数据传输量。本文将围绕PureScript语言，结合Intersection Observer API，实现图片懒加载功能，并探讨其封装与优化。
PureScript 简介
PureScript 是一种函数式编程语言，它基于 Haskell，旨在提供一种简洁、高效、易于维护的编程方式。PureScript 具有强大的类型系统、丰富的标准库和良好的编译优化，使其在编写大型应用程序时具有显著优势。
Intersection Observer API 简介
Intersection Observer API 是一种现代浏览器提供的原生API，用于异步观察目标元素与其祖先元素或顶级文档视窗（viewport）交叉状态的变化。该API可以轻松实现图片懒加载、无限滚动等功能，无需依赖第三方库。
图片懒加载原理
图片懒加载的基本原理是：在页面加载过程中，只加载可视区域内的图片，当用户滚动页面，即将进入可视区域的图片才会被加载。这样可以减少初始页面加载时间，提高用户体验。
PureScript 图片懒加载封装
以下是一个使用PureScript和Intersection Observer API实现图片懒加载的示例代码：
```purs
module LazyLoad where
import Effect (Effect)
import Effect.Aff (Aff)
import Effect.Class (liftEffect)
import DOM (document, querySelectorAll, Element)
import DOM.Event.Event (Event)
import DOM.Node (Node, parentNode)
import DOM.Node.NodeType (NodeTypeName)
import DOM.Node.Types (NodeName)
import DOM.Node.ReadableStream (ReadableStream)
import DOM.WebSocket (WebSocket)
import Data.Array (Array, foldl, (:))
import Data.Functor (())
import Data.Maybe (Maybe, fromMaybe)
import Data.Nullable (Nullable, toMaybe)
import Data.String (joinWith)
import Effect.Aff (Aff, launchAff_, attempt)
import Effect.Aff.Class (liftAff)
import Effect.Class.Console (log)
import Effect-dom (DOM)
import Effect-dom.Event (addEventListener, preventDefault)
import Effect-dom.Node (NodeName, querySelectorAll, textContent)
import Effect-dom.Node.Types (Node)
import Effect-dom.Window (window)
import Foreign (Foreign)
import Foreign.Object (Object)
import Prelude (Unit, ($), (<<<), (), (>>=), (==), (&&), (||), (<<>>), (==), (), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<>>), (<<<), (
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