The document introduces scope.js, a mini framework concerning Angular's core functionalities. It discusses how scope maintains separation of concerns, facilitates data sharing, implements a dirty-checking mechanism, and utilizes $watch and $digest for data-binding. It emphasizes the importance of managing watchers to avoid performance issues and provide reliable data updates.

1. Scope.js
A mini framework

2. Introduction
What do you think is the nucleus of angular?

3. What problem is scope trying to solve?
separation of concerns
-Scope attempts to ensure/helps in maintaining
proper separation of concerns between the
model and the view.
-It helps in sharing of data between different
parts of application.
-watching for changing in data.

4. Dirty-checking mechanism
Angular implements a dirty-checking
mechanism,using which you can get notified
when a piece of data on a scope changes.It is
also the source of data-binding.

5. Scope object
a plain-simple javascript object.
function Scope() {
}

6. $watch and $digest
This is where the magic happens

7. $watch
with $watch we can attach a watcher to a scope.
we create a watcher by providing two functions to $watch
1)A watch function() which specifies the piece of data you
are interested in.
2)A listener function() which will be called whenever the
data changes.

8. $digest()
It iterates over all the watchers that has been
attached on the scope,and runs their watch and
listener functions accordingly.

9. triggering chained watches in the
same digest()
the listener functions themselves may change
the property on the scope,if this happens and
there is another watcher looking for the
property that have just changed,it might not
notice the change during the same digest pass

10. the unstable state
what happens if there are two watches looking
at change made by each other?

11. Performance characteristics
Every time a $watch is called on the scope or a
value is bound from DOM with interpolation(ng-
repeat,ng-switch,ng-if,or any other dom
attribute a function gets added to
$$watchers),so always remember to unbind the
watchers.

12. Thank you
About me:
A javascript frontend developer
twitter:@atishaybaid
github:@atishaybaid
blog:atishaybaid.com