File System Access API

const dirHandle = await navigator.storage.getDirectory(); // 储存在 OPFS 中，不需要用户授权

const [fileHandle] = await window.showOpenFilePicker();

const handle = await window.showSaveFilePicker(opts);

// File handles are serializable，可以储存在 IndexedDB、传输，需要用户授权

fileHandle.requestPermission(opts)

const dirHandle = await window.showDirectoryPicker();

const newDirectoryHandle = await existingDirectoryHandle.getDirectoryHandle('My Documents', { create: true });

const newFileHandle = await newDirectoryHandle.getFileHandle('My Notes.txt', { create: true });

const path = await newDirectoryHandle.resolve(newFileHandle);

await directoryHandle.removeEntry('Old Stuff', { recursive: true });

之前叫 Native File System API

await window.chooseFileSystemEntries(); // 修改参数打开新文件，写文件后关闭时有保存窗口，需要用户手势

const file = await fileHandle.getFile();

const contents = await file.text();

async function writeFile(fileHandle, contents) {

// Create a writer (request permission if necessary).

const writer = await fileHandle.createWriter();

// Write the full length of the contents

await writer.write(0, contents);

// Close the file and write the contents to disk

await writer.close();

}

// 目前不允许后台（sw）访问

// 老的 File and Directory Entries API 虚拟文件系统

// 只有拖拽才能访问该文件系统