[removed] What are .extend and .prototype used for?

Question

I am relatively new to JavaScript and keep seeing .extend and .prototype in third party libraries I am using. I thought it had to do with the Prototype javascript library, b

Answer 1

This seems to be the clearest and simplest example to me, this just appends property or replaces existing.

function replaceProperties(copyTo, copyFrom)  {
  for (var property in copyFrom) 
    copyTo[property] =  copyFrom[property]
  return copyTo
}