How make default profile picture in express js

How can I can make default profile picture when the user have not upload there picture? I want to display default profile picture for them, like png.
I have done some thing similar in php but I don’t know how to change it to nodejs express code. This is what have done in php:

$target_dir = "uploads/";
$defaultProfilePicture = "static/" . basename("0000.png");
$defaultContentType = "image/png;";

How can I change it to express code? Please help me by saving my days. Thanks

Answer

If your using mongoose in your user model make a field for profile picture and you can set a default value

Example

const schema = new Schema({
  name: String,
  role: { type: String, default: 'guitarist' }
});