JavaScript使用webcomponent的简单示例
官方网站:
Web Component - Web API 接口参考 | MDN
1. 给一个html文件的路径字符串path, 存储对应path下的template,script,style数据
1) 传入path
2) 使用fetch将path字符串所在的文件找到并返回内容
const res = await fetch(path).then(res => res.text());
3) 使用DOMParser实例的parseFromString方法将至转换为shadowRoot
const parser = new DOMParser();
const doc = parser.parseFromString(res, "text/html"); // shadowRoot
4) shadowRoot支持dom查找元素的方法, 可以找到template, script, style标签元素
5) 根据不同的path, 存放相应的template, script, style
// 动态加载组件并解析
async function loadComponent(path, name) {this.caches = this.caches || {};// 当缓存存在if (!!this.caches[path]) {return this.caches[path]}const res = await fetch(path).then(res => res.text());// 利用DOMParser,生成shaow-rootconst parser = new DOMParser();const doc = parser.parseFromString(res, "text/html");// 解析模板，脚本，样式const template = doc.querySelector("template");const script = doc.querySelector("script");const style = doc.querySelector("style");// 缓存内容this.caches[path] = {template,script,style}return this.caches[path]
}2. custom-component.js(自定义标签custom-component)
// 容器组件
class CustomComponent extends HTMLElement {async connectedCallback() {console.log("custom-component connected");// 获取组件的path，即html的路径const strPath = this.getAttribute("path");// 加载htmlconst cInfos = await loadComponent(strPath);// Element.attachShadow() 方法给指定的元素挂载一个 Shadow DOM，并且返回对 ShadowRoot 的引用。const shadow = this.attachShadow({ mode: "closed" });// 添加html对应的标签和内容this._addElements(shadow, cInfos);}_addElements(shadow, info) {if (info.template) {shadow.appendChild(info.template.content.cloneNode(true));}if (info.script) {var fn = new Function(`${info.script.textContent}`);// 绑定脚本的this为当前的影子根节点, 防止全局污染fn.call(shadow);}if (info.style) {shadow.appendChild(info.style);}}
}
window.customElements.define("custom-component", CustomComponent);使用自定义标签custom-component
// 使用示例: renderComponent.call(thisArg, route)
function renderComponent(route) {var el = document.createElement("custom-component");el.setAttribute("path", `/${route.component}.html`);// append可以追加节点和字符串，appendChild只能追加节点；el.id = "_route_";this.append(el);
}1) 先新建goods.html
<template><div>商品详情-goos</div><div class="product-id">下面商品是????</div>
</template><script>alert('这是商品页!!!')
</script><style>.product-id{color: red;}
</style>
2) 在index.html使用
先引入custom-component.js
然后在index.html的script标签写:
renderComponent.call(document.getElementById('box'), {component: './goods'})index.html文件代码
<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>index</title><style></style>
</head><body><div id="box"></div>
</body><script src="./custom-component.js"></script><script>renderComponent.call(document.getElementById('box'), {component: './goods'})</script>
</html>