节点：fs.readdir() 总是返回文件

Question

I have this code snippet:

fs.readdir(STLFilesDir, (err, files) => {
            if (err)
            {
                console.log(err);
                throw err;
            }
            if (files)
            {
                console.log(files); //files is an array with all the files in the directory
                res.render('prerenderer.ejs');
            }   
            else 
            {
                console.log('no files found');
                res.render('prerenderer.ejs');
            }

However, in the case of not having any files in the folder, I dont't get what is expected. Instead of seeing no files found, in the console. I get this [] . This is an empty object. This means that the last else does not work. So fs.readdir() always returns an array - even if it's empty. So how can I get the else portion to run?

Answer 1

在javascript中，空数组[]是真的，所以你需要if (files.length)而不是if (files)