TypeError cannot read property 'length' of undefined in node js

Question

my code app.js
it is to upload some of imges I am getting the "TypeError: Cannot read property 'length' of undefined?

app.post('/upload', urlencodedParser, function(req, res) {
    if (req.url == '/upload') {
        var form = new formidable.IncomingForm();
        form.uploadDir = "C:/Users/Abdulrahman Afify/myapp/";
        form.keepExtensions = true;
        form.multiples = true;
        form.parse(req, function(err, fields, files) {
            if (err) {
                res.json({
                    results: "faild",
                    data: {},
                    message: 'Cannot upload Files Error is: ${err}'
                });
            }
            var arrayOffiles = files[""];
            if (arrayOffiles.length > 0) {
                var fileNames = [];
                arrayOffiles.forEach((eachFile) => {
                    fileNames.push(eachFile.path);
                });
                res.json({
                    result: "OK",
                    Date: fileNames,
                    numberOfImages: fileNames.length,
                    message: "upload images Successfully"
                });
            } else {
                res.json({
                    result: "failed",
                    Date: [],
                    numberOfImages: 0,
                    message: "upload images failed"
                });
             }
        });
    } else {
        res.writeHead(200, {
            'Content-Type': 'text/html'
        });
        res.write('<form action="fileupload" method="post" enctype="multipart/form-data">');
        res.write('<input type="file" name="filetoupload"  multiple ><br>');
        res.write('<input type="submit">');
        res.write('</form>');
        return res.end();
    }
});

ERROR: { if(arrayOffiles.length > 0){ TypeError: Cannot read property 'length' of undefined}

how can i solve it please in node.js

Answer 1

Use this

var arrayOffiles= files || [];

Instead

var arrayOffiles= files[""];