Web realizes local computer tree directory, reads local folder, output file content, dynamic binding event, file handle, recursion, showDirectoryPicker, entries, getFile, createElement

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foreword

Currently, it supports the reading of code files such as .txt, .html, .JavaScript, etc., but does not support the reading of pictures or document types..css

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renderings

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html

<div class="p_20 bs_bb">
	<div class="d_f jc_c">
		<button id="idFolder" class="w_50_ fs_30 cursor_pointer">打开文件夹</button>
	</div>
	
	<div id="idContent" class="m_t_20 bs_bb p_20 bc_rgba_192_1"></div>
</div>

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JavaScript

// 全局文件句柄
// 多处用到此变量
// 所以定义到全局
let root = [];

// 打开文件夹(导入文件夹)
idFolder.onclick = async function () {
    
    
	try {
    
    
		let handle = await showDirectoryPicker(),
			node = document.querySelector('#idContent');
		
		root = await processHandle(handle);
		
		createTreeDirectory(node, root.children);
	} catch (error) {
    
    
		console.log(error);
		// 用户拒绝的处理
	}
};

// 进程句柄(获取文件夹中的文件夹句柄和文件句柄)
async function processHandle(handle) {
    
    
	if (handle.kind === 'file') return handle;
	
	// 注意这个地方
	// 不可以定义新变量接收数据
	// 否则文件夹句柄将不能保存
	handle.children = [];
	// 得到异步迭代器
	let iter = handle.entries();
	
	for await (let item of iter) handle.children.push(await processHandle(item[1]));
	
	return handle;
}

// 通过递归创建树形目录
function createTreeDirectory(node, data) {
    
    
	const ul = document.createElement("ul");
	
	ul.className = "p_l_20";
	node.appendChild(ul);
	
	data.forEach((item) => {
    
    
		let li = document.createElement("li");
		
		li.className = item.kind === 'file' ? 'fs_18 w_fc cursor_pointer' : '';
		// 动态绑定事件
		if (item.kind === 'file') li.onclick = handleFileContent;
		
		ul.appendChild(li);
		
		if (item.children && item.children.length > 0) {
    
    
			const details = document.createElement("details");
			
			li.appendChild(details);
			
			const summary = document.createElement("summary");
			
			summary.className = item.kind === 'directory' ? "fs_18 w_fc cursor_default" : "";
			summary.textContent = item.name;
			details.appendChild(summary);
			
			createTreeDirectory(details, item.children);
		} else {
    
    
			li.textContent = item.name;
		}
	});
}

// 文件点击事件
function handleFileContent({
     
      target: {
     
      innerText } }) {
    
    
	getFileHandle(root.children, innerText);
}

// 通过递归获取指定文件句柄
function getFileHandle(data, name) {
    
    
	for (let i = 0; i < data.length; i++) {
    
    
		let item = data[i];
		
		if (item.name === name) {
    
    
			return readText(item);
		} else {
    
    
			if (item.children && item.children.length > 0) {
    
    
				let res = getFileHandle(item.children, name);
				
				if (res) return res;
			}
		}
	}
}

// 输出文件内容
async function readText(fileHandle) {
    
    
	let file = await fileHandle.getFile(),
		reader = new FileReader();
	
	reader.onload = ({
     
      target: {
     
      result } }) => {
    
    
		console.log(`-------输出结果-------\n${
      
      result}`);
	}
	
	reader.readAsText(file, 'utf-8');
}