JavaScript: What are .extend and .prototype used for?

user_48523 0
Viewed 142307

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, but I am beginning to think that is not the case. What are these used for?

object-model prototype javascript
7 Answers
  • .extends() create a class which is a child of another class.
    behind the scenes Child.prototype.__proto__ sets its value to Parent.prototype
    so methods are inherited.
  • .prototype inherit features from one to another.
  • .__proto__ is a getter/setter for Prototype.
user_119774120

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
}
user_88812510
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