<s>
AngularJS	B-Application
is	O
a	O
discontinued	O
free	B-License
and	I-License
open-source	I-License
JavaScript-based	O
web	B-Application
framework	I-Application
for	O
developing	O
single-page	B-Application
applications	I-Application
.	O
</s>
<s>
It	O
was	O
maintained	O
mainly	O
by	O
Google	B-Application
and	O
a	O
community	O
of	O
individuals	O
and	O
corporations	O
.	O
</s>
<s>
It	O
aimed	O
to	O
simplify	O
both	O
the	O
development	O
and	O
the	O
testing	O
of	O
such	O
applications	O
by	O
providing	O
a	O
framework	O
for	O
client-side	O
model	O
–	O
view	O
–	O
controller	O
(	O
MVC	O
)	O
and	O
model	O
–	O
view	O
–	O
viewmodel	O
(	O
MVVM	O
)	O
architectures	O
,	O
along	O
with	O
components	O
commonly	O
used	O
in	O
web	B-Application
applications	I-Application
and	O
progressive	B-Application
web	I-Application
applications	I-Application
.	O
</s>
<s>
AngularJS	B-Application
was	O
used	O
as	O
the	O
frontend	O
of	O
the	O
MEAN	B-Application
stack	I-Application
,	O
that	O
consisted	O
of	O
MongoDB	B-Application
database	O
,	O
Express.js	B-Language
web	B-Application
application	I-Application
server	O
framework	O
,	O
AngularJS	B-Application
itself	O
(	O
or	O
Angular	B-Language
)	O
,	O
and	O
Node.js	B-Language
server	O
runtime	O
environment	O
.	O
</s>
<s>
As	O
of	O
January	O
1	O
,	O
2022	O
,	O
Google	B-Application
no	O
longer	O
updates	O
AngularJS	B-Application
to	O
fix	O
security	O
,	O
browser	O
compatibility	O
,	O
or	O
jQuery	B-Language
issues	O
.	O
</s>
<s>
The	O
Angular	B-Language
team	O
recommends	O
upgrading	O
to	O
Angular	B-Language
(	O
v2+	O
)	O
as	O
the	O
best	O
path	O
forward	O
,	O
but	O
they	O
also	O
provided	O
some	O
other	O
options	O
.	O
</s>
<s>
The	O
AngularJS	B-Application
framework	O
worked	O
by	O
first	O
reading	O
the	O
HyperText	B-Language
Markup	I-Language
Language	I-Language
(	O
HTML	B-Language
)	O
page	O
,	O
which	O
had	O
additional	O
custom	O
HTML	B-General_Concept
attributes	I-General_Concept
embedded	O
into	O
it	O
.	O
</s>
<s>
Angular	B-Language
interpreted	O
those	O
attributes	O
as	O
directives	O
to	O
bind	O
input	O
or	O
output	O
parts	O
of	O
the	O
page	O
to	O
a	O
model	O
that	O
is	O
represented	O
by	O
standard	O
JavaScript	B-Language
variables	O
.	O
</s>
<s>
The	O
values	O
of	O
those	O
JavaScript	B-Language
variables	O
could	O
be	O
manually	O
set	O
within	O
the	O
code	O
or	O
retrieved	O
from	O
static	O
or	O
dynamic	O
JSON	B-General_Concept
resources	O
.	O
</s>
<s>
AngularJS	B-Application
was	O
built	O
on	O
the	O
belief	O
that	O
declarative	B-Language
programming	I-Language
should	O
be	O
used	O
to	O
create	O
user	B-Application
interfaces	I-Application
and	O
connect	O
software	O
components	O
,	O
while	O
imperative	B-Application
programming	I-Application
was	O
better	O
suited	O
to	O
defining	O
an	O
application	O
's	O
business	B-Architecture
logic	I-Architecture
.	O
</s>
<s>
The	O
framework	O
adapted	O
and	O
extended	O
traditional	O
HTML	B-Language
to	O
present	O
dynamic	O
content	O
through	O
two-way	O
data-binding	O
that	O
allowed	O
for	O
the	O
automatic	O
synchronization	O
of	O
models	O
and	O
views	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
AngularJS	B-Application
de-emphasized	O
explicit	O
Document	B-General_Concept
Object	I-General_Concept
Model	I-General_Concept
(	O
DOM	B-General_Concept
)	O
manipulation	O
with	O
the	O
goal	O
of	O
improving	O
testability	O
and	O
performance	O
.	O
</s>
<s>
AngularJS	B-Application
's	O
design	O
goals	O
included	O
:	O
</s>
<s>
to	O
decouple	O
DOM	B-General_Concept
manipulation	O
from	O
application	B-Architecture
logic	I-Architecture
.	O
</s>
<s>
to	O
decouple	O
the	O
client	O
side	O
of	O
an	O
application	O
from	O
the	O
server-side	B-Application
.	O
</s>
<s>
to	O
provide	O
structure	O
for	O
the	O
journey	O
of	O
building	O
an	O
application	O
:	O
from	O
designing	O
the	O
UI	B-Application
,	O
through	O
writing	O
the	O
business	B-Architecture
logic	I-Architecture
,	O
to	O
testing	O
.	O
</s>
<s>
AngularJS	B-Application
implemented	O
the	O
MVC	O
pattern	O
to	O
separate	O
presentation	O
,	O
data	O
,	O
and	O
logic	O
components	O
.	O
</s>
<s>
Using	O
dependency	B-Library
injection	I-Library
,	O
Angular	B-Language
brought	O
traditionally	O
server-side	B-Application
services	O
,	O
such	O
as	O
view-dependent	O
controllers	O
,	O
to	O
client-side	O
web	B-Application
applications	I-Application
.	O
</s>
<s>
AngularJS	B-Application
used	O
the	O
term	O
"	O
scope	B-Language
"	O
in	O
a	O
manner	O
akin	O
to	O
the	O
fundamentals	O
of	O
computer	O
science	O
.	O
</s>
<s>
Scope	B-Language
in	O
computer	O
science	O
describes	O
when	O
in	O
the	O
program	O
a	O
particular	O
binding	O
is	O
valid	O
.	O
</s>
<s>
The	O
ECMA-262	B-Language
specification	O
defines	O
scope	B-Language
as	O
:	O
a	O
lexical	B-Language
environment	I-Language
in	O
which	O
a	O
Function	O
object	O
is	O
executed	O
in	O
client-side	O
web	O
scripts	O
;	O
akin	O
to	O
how	O
scope	B-Language
is	O
defined	O
in	O
lambda	B-Language
calculus	I-Language
.	O
</s>
<s>
As	O
a	O
part	O
of	O
the	O
"	O
MVC	O
"	O
architecture	O
,	O
the	O
scope	B-Language
forms	O
the	O
"	O
Model	O
"	O
,	O
and	O
all	O
variables	O
defined	O
in	O
the	O
scope	B-Language
can	O
be	O
accessed	O
by	O
the	O
"	O
View	O
"	O
as	O
well	O
as	O
the	O
"	O
Controller	O
"	O
.	O
</s>
<s>
The	O
scope	B-Language
behaves	O
as	O
a	O
glue	O
and	O
binds	O
the	O
"	O
View	O
"	O
and	O
the	O
"	O
Controller	O
"	O
.	O
</s>
<s>
The	O
task	O
performed	O
by	O
the	O
AngularJS	B-Application
bootstrapper	O
occurred	O
in	O
three	O
phases	O
after	O
the	B-General_Concept
DOM	I-General_Concept
has	O
been	O
loaded	O
:	O
</s>
<s>
AngularJS	B-Application
directives	O
allowed	O
the	O
developer	O
to	O
specify	O
custom	O
and	O
reusable	O
HTML-like	O
elements	O
and	O
attributes	O
that	O
define	O
data	B-General_Concept
bindings	I-General_Concept
and	O
the	O
behavior	O
of	O
presentation	O
components	O
.	O
</s>
<s>
ng-animate	O
A	O
module	O
provides	O
support	O
for	O
JavaScript	B-Language
,	O
CSS3	O
transition	O
and	O
CSS3	O
keyframe	O
animation	O
hooks	O
within	O
existing	O
core	O
and	O
custom	O
directives	O
.	O
</s>
<s>
Since	O
ng-*	O
attributes	O
are	O
not	O
valid	O
in	O
HTML	B-Language
specifications	O
,	O
data-ng-*	O
can	O
also	O
be	O
used	O
as	O
a	O
prefix	O
.	O
</s>
<s>
For	O
example	O
,	O
both	O
ng-app	O
and	O
data-ng-app	O
are	O
valid	O
in	O
AngularJS	B-Application
.	O
</s>
<s>
ng-app	O
Declares	O
the	O
root	O
element	O
of	O
an	O
AngularJS	B-Application
application	O
,	O
under	O
which	O
directives	O
can	O
be	O
used	O
to	O
declare	O
bindings	O
and	O
define	O
behavior	O
.	O
</s>
<s>
ng-aria	O
A	O
module	O
for	O
accessibility	O
support	O
of	O
common	O
ARIA	B-General_Concept
attributes	I-General_Concept
.	O
</s>
<s>
ng-bind	O
Sets	O
the	O
text	O
of	O
a	O
DOM	B-General_Concept
element	O
to	O
the	O
value	O
of	O
an	O
expression	O
.	O
</s>
<s>
Any	O
change	O
to	O
the	O
variable	O
‘	O
name’	O
in	O
the	O
application	O
's	O
scope	B-Language
reflect	O
instantly	O
in	O
the	B-General_Concept
DOM	I-General_Concept
.	O
</s>
<s>
ng-controller	O
Specifies	O
a	O
JavaScript	B-Language
controller	O
class	O
that	O
evaluates	O
HTML	B-Language
expressions	O
.	O
</s>
<s>
When	O
the	O
condition	O
is	O
false	O
,	O
the	O
element	O
is	O
removed	O
from	O
the	B-General_Concept
DOM	I-General_Concept
.	O
</s>
<s>
ng-model	O
Similar	O
to	O
ng-bind	O
,	O
but	O
establishes	O
a	O
two-way	O
data	B-General_Concept
binding	I-General_Concept
between	O
the	O
view	O
and	O
the	O
scope	B-Language
.	O
</s>
<s>
ng-view	O
The	O
base	O
directive	O
responsible	O
for	O
handling	O
routes	O
that	O
resolve	O
JSON	B-General_Concept
before	O
rendering	O
templates	O
driven	O
by	O
specified	O
controllers	O
.	O
</s>
<s>
AngularJS	B-Application
two-way	O
data	B-General_Concept
binding	I-General_Concept
had	O
its	O
most	O
notable	O
feature	O
,	O
largely	O
relieving	O
the	O
server	O
backend	O
of	O
templating	O
responsibilities	O
.	O
</s>
<s>
Instead	O
,	O
templates	O
were	O
rendered	O
in	O
plain	O
HTML	B-Language
according	O
to	O
data	O
contained	O
in	O
a	O
scope	B-Language
defined	O
in	O
the	O
model	O
.	O
</s>
<s>
The	O
$scope	O
service	O
in	O
Angular	B-Language
detected	O
changes	O
to	O
the	O
model	O
section	O
and	O
modified	O
HTML	B-Language
expressions	O
in	O
the	O
view	O
via	O
a	O
controller	O
.	O
</s>
<s>
This	O
circumvented	O
the	O
need	O
to	O
actively	O
manipulate	O
the	B-General_Concept
DOM	I-General_Concept
and	O
encouraged	O
bootstrapping	O
and	O
rapid	O
prototyping	O
of	O
web	B-Application
applications	I-Application
.	O
</s>
<s>
AngularJS	B-Application
detected	O
changes	O
in	O
models	O
by	O
comparing	O
the	O
current	O
values	O
with	O
values	O
stored	O
earlier	O
in	O
a	O
process	O
of	O
dirty-checking	O
,	O
unlike	O
Ember.js	B-Language
and	O
Backbone.js	B-Language
that	O
triggered	O
listeners	O
when	O
the	O
model	O
values	O
are	O
changed	O
.	O
</s>
<s>
is	O
an	O
angular	B-Language
method	O
used	O
for	O
dirty	O
checking	O
.	O
</s>
<s>
Any	O
variable	O
or	O
expression	O
assigned	O
in	O
$scope	O
automatically	O
sets	O
up	O
a	O
in	O
angular	B-Language
.	O
</s>
<s>
all	O
create	O
watches	O
in	O
angular	B-Language
scope	B-Language
automatically	O
.	O
</s>
<s>
Different	O
ways	O
of	O
defining	O
a	O
watcher	O
in	O
AngularJS	B-Application
.	O
</s>
<s>
$scope.$watch('person.username', validateUnique )	O
;	O
</s>
<s>
place	O
an	O
interpolation	O
in	O
your	O
template	O
(	O
a	O
watcher	O
will	O
be	O
created	O
for	O
you	O
on	O
the	O
current	O
$scope	O
)	O
.	O
</s>
<s>
is	O
angular	B-Language
method	O
that	O
is	O
invoked	O
internally	O
by	O
angularjs	B-Application
in	O
frequent	O
intervals	O
.	O
</s>
<s>
In	O
method	O
,	O
angular	B-Language
iterates	O
over	O
all	O
in	O
its	O
scope/child	O
scopes	O
.	O
</s>
<s>
is	O
an	O
angular	B-Language
method	O
that	O
internally	O
invokes	O
.	O
</s>
<s>
is	O
both	O
a	O
method	O
and	O
event	O
in	O
angularjs	B-Application
.	O
</s>
<s>
method	O
,	O
removes	O
a	O
scope	B-Language
and	O
all	O
its	O
children	O
from	O
dirty	O
checking	O
.	O
</s>
<s>
event	O
is	O
called	O
by	O
angular	B-Language
whenever	O
a	O
$scope	O
or	O
$controller	O
is	O
destroyed	O
.	O
</s>
<s>
AngularJS	B-Application
was	O
originally	O
developed	O
in	O
2009	O
by	O
Miško	O
Hevery	O
at	O
Brat	O
Tech	O
LLC	O
as	O
the	O
software	O
behind	O
an	O
online	O
JSON	B-General_Concept
storage	O
service	O
,	O
that	O
would	O
have	O
been	O
priced	O
by	O
the	O
megabyte	O
,	O
for	O
easy-to-make	O
applications	O
for	O
the	O
enterprise	O
.	O
</s>
<s>
This	O
venture	O
was	O
located	O
at	O
the	O
web	O
domain	O
"	O
GetAngular.com	O
 "	O
,	O
and	O
had	O
a	O
few	O
subscribers	O
,	O
before	O
the	O
two	O
decided	O
to	O
abandon	O
the	O
business	O
idea	O
and	O
release	O
Angular	B-Language
as	O
an	O
open-source	O
library	O
.	O
</s>
<s>
The	O
1.6	O
release	O
added	O
many	O
of	O
the	O
concepts	O
of	O
Angular	B-Language
to	O
AngularJS	B-Application
,	O
including	O
the	O
concept	O
of	O
a	O
component-based	O
application	O
architecture	O
.	O
</s>
<s>
In	O
January	O
2018	O
,	O
a	O
schedule	O
was	O
announced	O
for	O
phasing-out	O
AngularJS	B-Application
:	O
after	O
releasing	O
1.7.0	O
,	O
the	O
active	O
development	O
on	O
AngularJS	B-Application
would	O
continue	O
till	O
June	O
30	O
,	O
2018	O
.	O
</s>
<s>
Versions	O
1.3	O
and	O
later	O
of	O
AngularJS	B-Application
did	O
not	O
support	O
Internet	B-Application
Explorer	I-Application
8	I-Application
or	O
earlier	O
.	O
</s>
<s>
While	O
AngularJS	B-Application
1.2	O
supported	O
IE8	B-Application
,	O
its	O
team	O
does	O
not	O
.	O
</s>
<s>
Subsequent	O
versions	O
of	O
AngularJS	B-Application
are	O
simply	O
called	O
Angular	B-Language
.	O
</s>
<s>
Angular	B-Language
is	O
an	O
incompatible	O
TypeScript-based	O
rewrite	O
of	O
AngularJS	B-Application
.	O
</s>
<s>
Angular	B-Language
4	I-Language
was	O
announced	O
on	O
13	O
December	O
2016	O
,	O
skipping	O
3	O
to	O
avoid	O
a	O
confusion	O
due	O
to	O
the	O
misalignment	O
of	O
the	O
router	O
package	O
's	O
version	O
which	O
was	O
already	O
distributed	O
as	O
v3.3.0	O
.	O
</s>
<s>
AngularDart	O
works	O
on	O
Dart	B-Language
,	O
which	O
is	O
an	O
object-oriented	B-Language
,	O
class	B-Application
defined	I-Application
,	O
single	O
inheritance	O
programming	O
language	O
using	O
C	B-Application
style	O
syntax	O
,	O
that	O
is	O
different	O
from	O
Angular	B-Application
JS	I-Application
(	O
which	O
uses	O
JavaScript	B-Language
)	O
and	O
Angular	O
2/	O
Angular	B-Language
4	I-Language
(	O
which	O
uses	O
TypeScript	B-Language
)	O
.	O
</s>
<s>
Angular	B-Language
4	I-Language
released	O
in	O
March	O
2017	O
,	O
with	O
the	O
framework	O
's	O
version	O
aligned	O
with	O
the	O
version	O
number	O
of	O
the	O
router	O
it	O
used	O
.	O
</s>
<s>
Angular	B-Language
5	O
was	O
released	O
on	O
November	O
1	O
,	O
2017	O
.	O
</s>
<s>
Key	O
improvements	O
in	O
Angular	B-Language
5	O
include	O
support	O
for	O
progressive	B-Application
Web	I-Application
apps	I-Application
,	O
a	O
build	O
optimizer	O
and	O
improvements	O
related	O
to	O
Material	B-Application
Design	I-Application
.	O
</s>
<s>
Angular	B-Language
6	O
was	O
released	O
on	O
3	O
May	O
2018	O
,	O
Angular	B-Language
7	O
was	O
released	O
on	O
18	O
October	O
2018	O
,	O
and	O
Angular	B-Language
8	O
was	O
released	O
on	O
May	O
28	O
,	O
2019	O
.	O
</s>
<s>
Angular	B-Language
follows	O
Semantic	O
Versioning	O
standards	O
,	O
with	O
each	O
major	O
version	O
number	O
indicating	O
potentially	O
breaking	O
changes	O
.	O
</s>
<s>
Angular	B-Language
has	O
pledged	O
to	O
provide	O
6	O
months	O
of	O
active	O
support	O
for	O
each	O
major	O
version	O
followed	O
by	O
12	O
months	O
of	O
long	O
term	O
support	O
.	O
</s>
<s>
A	O
normal	O
Angular	B-Language
application	O
executes	O
in	O
the	O
browser	O
,	O
while	O
Angular	B-Language
Universal	O
generates	O
static	O
application	O
pages	O
on	O
the	O
server	O
through	O
server-side	B-Application
rendering	O
(	O
SSR	O
)	O
.	O
</s>
<s>
AngularJS	B-Application
Material	O
was	O
a	O
UI	B-Application
component	O
library	O
that	O
implemented	O
Material	B-Application
Design	I-Application
in	O
AngularJS	B-Application
.	O
</s>
<s>
The	O
library	O
provided	O
a	O
set	O
of	O
reusable	O
,	O
well-tested	O
,	O
and	O
accessible	O
UI	B-Application
components	O
.	O
</s>
<s>
The	O
AngularJS	B-Application
Material	O
library	O
is	O
a	O
mature	O
and	O
stable	O
product	O
that	O
is	O
ready	O
for	O
production	O
use	O
and	O
works	O
only	O
with	O
AngularJS	B-Application
1.x	O
.	O
</s>
<s>
The	O
Angular	B-Language
Material	O
library	O
is	O
available	O
in	O
the	O
angular/material2	O
.	O
</s>
<s>
In	O
July	O
2012	O
,	O
the	O
Angular	B-Language
team	O
built	O
an	O
extension	O
for	O
the	B-Application
Google	I-Application
Chrome	B-Application
browser	I-Application
called	O
Batarang	O
,	O
that	O
improved	O
the	O
debugging	O
experience	O
for	O
web	B-Application
applications	I-Application
built	O
with	O
Angular	B-Language
.	O
</s>
<s>
For	O
a	O
time	O
during	O
late	O
2014	O
and	O
early	O
2015	O
,	O
the	O
extension	O
was	O
not	O
compatible	O
with	O
recent	O
releases	O
(	O
after	O
v1.2.x	O
)	O
of	O
Angular	B-Language
.	O
</s>
<s>
AngularJS	B-Application
set	O
out	O
the	O
paradigm	O
of	O
a	O
digest	O
cycle	O
.	O
</s>
<s>
This	O
cycle	O
could	O
be	O
considered	O
a	O
loop	O
,	O
during	O
which	O
AngularJS	B-Application
checked	O
if	O
there	O
were	O
any	O
changes	O
to	O
all	O
the	O
variables	O
watched	O
by	O
all	O
the	O
$scopes	O
.	O
</s>
<s>
If	O
$	O
scope.myVar	O
is	O
defined	O
in	O
a	O
controller	O
and	O
this	O
variable	O
was	O
marked	O
for	O
watching	O
,	O
Angular	B-Language
would	O
monitor	O
the	O
changes	O
on	O
myVar	O
in	O
each	O
loop	O
iteration	O
.	O
</s>
<s>
This	O
approach	O
potentially	O
led	O
to	O
slow	O
rendering	O
when	O
AngularJS	B-Application
checked	O
on	O
too	O
many	O
variables	O
in	O
the	O
$scope	O
every	O
cycle	O
.	O
</s>
