How to create a filetree from the webbrowser drop event.

filetreeFromDropEvent.js

const traverseFiles = async (item) => {
	if(item.isFile){
		return { file: item.file(), path: item.fullPath };
	}else if(item.isDirectory){
		const entries = await new Promise(resolve => item.createReader().readEntries(resolve));
		const files = await Promise.all(entries.map(traverseFiles));
		return { path: item.fullPath, files };
	}
}

document.getElementById("#drop").addEventListener("drop", (event) => {
	const filetree = Promise.all(
		Array.from(event.dataTransfer.items).map(item =>
			traverseFiles(item.webkitGetAsEntry())
	))
})