How to Mongoose send different value on find of specific field

I have a field which contain url to an image which is protected. It needs a secret to access file and the secret expire after a time. I want that when I do Mode.find() then the url value get replaced by anther url which contains the secret. So, that I don’t have to manually every where I find from the model.

const schema = new Schema({
  url:String
})

const Model = model('ModelName', Schema)

• Saved url in database

url:"id_of_image.jpg"

• Expected url when find

url:"/uploads/id_of_image.jpg?secret=xxxxxxxxxxxxxxxxx"

Answer

In this case, you can use virtuals. Something like:

const schema = new Schema({
  url:String
}, {
  // use these options to include virtual fields in response
  toJSON: { virtuals: true },
  toObject: { virtuals: true }
});

schema.virtual('secretUrl').get(function() {
  return this.url + ' ' + yourSecret;
});

Or if you want to replace your url field with secret url, you can use getters.