Generate javascript object name by appending string to object

Question

I am getting a Javascript object req.files . This object can have multiple files under it. req.files is an object and not an array.

So of if user adds three files, the object will look like:

req.files.file0
req.files.file1
req.files.file2

where file0, file1 etc is another object.

User can add upto 15 files. How can I check loop over such objects & read information from req.files.fileX ? I need to support IE 11 & chrome.

Answer 1

You can use bracket notation to access the properties of an object by a string. Try this:

for (var i = 0; i < Object.keys(req.files).length; i++) {
    var file = req.files['file' + i];
    if (file) {
        // use file here...
    }
}

Example fiddle

Answer 2

So I'm assuming your req object looks like this:

var req = {
  files: {
    file0: {},
    file1: {},
    file2: {},
    //...
    file14: {}
  }
};

If so, you can reference the file like this: req.files['file0']

So your loop could look like this:

for (prop in req.files) {
    var file = req.files[prop];
}

But you don't even need to use a loop:

var getReqFile = function(x){
  return req.files['file' + x] || null;
}
var file = getReqFile(5);