<s>
React	B-Application
(	O
also	O
known	O
as	O
React.js	B-Application
or	O
ReactJS	B-Application
)	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
front-end	B-Architecture
JavaScript	B-Language
library	I-Language
for	O
building	O
user	B-Application
interfaces	I-Application
based	O
on	O
components	B-Architecture
.	O
</s>
<s>
React	B-Application
can	O
be	O
used	O
as	O
a	O
base	O
in	O
the	O
development	O
of	O
single-page	B-Application
,	O
mobile	O
,	O
or	O
server-rendered	O
applications	O
with	O
frameworks	O
like	O
Next.js	B-Language
.	O
</s>
<s>
However	O
,	O
React	B-Application
is	O
only	O
concerned	O
with	O
the	O
user	B-Application
interface	I-Application
and	O
rendering	O
components	B-Architecture
to	O
the	B-General_Concept
DOM	I-General_Concept
,	O
so	O
creating	O
React	B-Application
applications	O
usually	O
requires	O
the	O
use	O
of	O
additional	O
libraries	O
for	O
routing	O
,	O
as	O
well	O
as	O
certain	O
client-side	O
functionality	O
.	O
</s>
<s>
The	O
following	O
is	O
a	O
rudimentary	O
example	O
of	O
using	O
React	B-Application
for	O
the	O
web	O
,	O
written	O
in	O
JSX	B-Language
and	O
JavaScript	B-Language
.	O
</s>
<s>
based	O
on	O
the	O
HTML	B-Language
document	O
below	O
.	O
</s>
<s>
The	O
Greeting	O
function	O
is	O
a	O
React	B-Application
component	O
that	O
displays	O
the	O
famous	O
introductory	O
''	O
Hello	O
,	O
world	O
"	O
.	O
</s>
<s>
React	B-Application
adheres	O
to	O
the	O
declarative	B-Language
programming	I-Language
paradigm	O
(	O
a	O
programming	O
paradigm	O
)	O
.	O
</s>
<s>
Developers	O
design	O
views	O
for	O
each	O
state	O
of	O
an	O
application	O
,	O
and	O
React	B-Application
updates	O
and	O
renders	O
components	B-Architecture
when	O
data	O
changes	O
.	O
</s>
<s>
This	O
is	O
in	O
contrast	O
with	O
imperative	B-Application
programming	I-Application
.	O
</s>
<s>
React	B-Application
code	O
is	O
made	O
of	O
entities	O
called	O
components	B-Architecture
.	O
</s>
<s>
These	O
components	B-Architecture
are	O
reusable	O
and	O
must	O
be	O
formed	O
in	O
the	O
SRC	O
folder	O
following	O
the	O
Pascal	O
Case	O
as	O
its	O
naming	O
convention	O
(	O
capitalize	O
camelCase	O
)	O
.	O
</s>
<s>
Components	B-Architecture
can	O
be	O
rendered	O
to	O
a	O
particular	O
element	O
in	O
the	B-General_Concept
DOM	I-General_Concept
using	O
the	O
React	B-Application
DOM	B-General_Concept
library	O
.	O
</s>
<s>
When	O
rendering	O
a	O
component	O
,	O
one	O
can	O
pass	O
the	O
values	O
between	O
components	B-Architecture
through	O
"	O
props	O
"	O
:	O
</s>
<s>
So	O
all	O
JSX	B-Language
elements	O
and	O
components	B-Architecture
are	O
bound	O
into	O
a	O
single	O
tag	O
.	O
</s>
<s>
The	O
two	O
primary	O
ways	O
of	O
declaring	O
components	B-Architecture
in	O
React	B-Application
are	O
through	O
function	O
components	B-Architecture
and	O
class-based	O
components	B-Architecture
.	O
</s>
<s>
Function	O
components	B-Architecture
are	O
declared	O
with	O
a	O
function	O
that	O
then	O
returns	O
some	O
JSX	B-Language
.	O
</s>
<s>
From	O
React	B-Application
16.8	O
version	O
and	O
above	O
,	O
Functional	O
component	O
can	O
use	O
state	O
using	O
Hooks	O
.	O
</s>
<s>
On	O
February	O
16	O
,	O
2019	O
,	O
React	B-Application
16.8	O
was	O
released	O
to	O
the	O
public	O
.	O
</s>
<s>
The	O
release	O
introduced	O
React	B-Application
Hooks	O
.	O
</s>
<s>
Hooks	O
are	O
functions	O
that	O
let	O
developers	O
"	O
hook	O
into	O
"	O
React	B-Application
state	O
and	O
lifecycle	O
features	O
from	O
function	O
components	B-Architecture
.	O
</s>
<s>
Hooks	O
do	O
not	O
work	O
inside	O
classes	O
—	O
they	O
let	O
developers	O
use	O
React	B-Application
without	O
classes	O
.	O
</s>
<s>
React	B-Application
provides	O
a	O
few	O
built-in	O
hooks	O
like	O
useState	O
,	O
useContext	O
,	O
useReducer	O
,	O
useMemo	O
and	O
useEffect	O
.	O
</s>
<s>
Others	O
are	O
documented	O
in	O
the	O
Hooks	O
API	B-General_Concept
Reference	O
.	O
</s>
<s>
It	O
is	O
the	O
modern	O
way	O
to	O
handle	O
state	O
with	O
React	B-Application
.	O
</s>
<s>
Hooks	O
should	O
only	O
be	O
called	O
from	O
React	B-Application
function	O
components	B-Architecture
and	O
custom	O
hooks	O
,	O
not	O
normal	O
functions	O
or	O
class	O
components	B-Architecture
.	O
</s>
<s>
Although	O
these	O
rules	O
ca	O
n't	O
be	O
enforced	O
at	O
runtime	O
,	O
code	O
analysis	O
tools	O
such	O
as	O
linters	B-Device
can	O
be	O
configured	O
to	O
detect	O
many	O
mistakes	O
during	O
development	O
.	O
</s>
<s>
Class-based	O
components	B-Architecture
are	O
declared	O
using	O
ES6	B-Language
classes	O
.	O
</s>
<s>
Where	O
class	O
components	B-Architecture
are	O
all	O
about	O
the	O
use	O
of	O
classes	O
and	O
the	O
lifecycle	O
methods	O
,	O
functional	O
components	B-Architecture
have	O
hooks	O
to	O
deal	O
with	O
state	O
management	O
and	O
other	O
problems	O
which	O
arise	O
when	O
writing	O
code	O
in	O
React	B-Application
.	O
</s>
<s>
Another	O
notable	O
feature	O
is	O
the	O
use	O
of	O
a	O
virtual	O
Document	B-General_Concept
Object	I-General_Concept
Model	I-General_Concept
,	O
or	O
virtual	O
DOM	B-General_Concept
.	O
</s>
<s>
React	B-Application
creates	O
an	O
in-memory	B-General_Concept
data-structure	O
cache	O
,	O
computes	O
the	O
resulting	O
differences	O
,	O
and	O
then	O
updates	O
the	O
browser	O
's	O
displayed	O
DOM	B-General_Concept
efficiently	O
.	O
</s>
<s>
This	O
allows	O
the	O
programmer	O
to	O
write	O
code	O
as	O
if	O
the	O
entire	O
page	O
is	O
rendered	O
on	O
each	O
change	O
,	O
while	O
the	O
React	B-Application
libraries	O
only	O
render	O
subcomponents	O
that	O
actually	O
change	O
.	O
</s>
<s>
When	O
ReactDOM.render	O
is	O
called	O
again	O
for	O
the	O
same	O
component	O
and	O
target	O
,	O
React	B-Application
takes	O
the	O
existing	O
virtual	O
DOM	B-General_Concept
it	O
knows	O
about	O
last	O
time	O
it	O
rendered	O
the	O
element	O
tree	O
,	O
compares	O
it	O
to	O
whatever	O
new	O
thing	O
developers	O
want	O
to	O
render	O
,	O
and	O
determines	O
which	O
(	O
if	O
any	O
)	O
of	O
the	O
living	O
DOM	B-General_Concept
needs	O
to	O
change	O
.	O
</s>
<s>
Lifecycle	O
methods	O
for	O
class-based	O
components	B-Architecture
use	O
a	O
form	O
of	O
hooking	O
that	O
allows	O
the	O
execution	O
of	O
code	O
at	O
set	O
points	O
during	O
a	O
component	O
's	O
lifetime	O
.	O
</s>
<s>
componentDidMount	O
is	O
called	O
once	O
the	O
component	O
has	O
"	O
mounted	O
"	O
(	O
the	O
component	O
has	O
been	O
created	O
in	O
the	O
user	B-Application
interface	I-Application
,	O
often	O
by	O
associating	O
it	O
with	O
a	O
DOM	B-General_Concept
node	O
)	O
.	O
</s>
<s>
This	O
is	O
commonly	O
used	O
to	O
trigger	O
data	O
loading	O
from	O
a	O
remote	O
source	O
via	O
an	O
API	B-General_Concept
.	O
</s>
<s>
It	O
is	O
usually	O
called	O
every	O
time	O
the	O
component	O
's	O
state	O
is	O
updated	O
,	O
which	O
should	O
be	O
reflected	O
in	O
the	O
user	B-Application
interface	I-Application
.	O
</s>
<s>
JSX	B-Language
,	O
or	O
JavaScript	B-Language
Syntax	O
Extension	O
,	O
is	O
an	O
extension	O
to	O
the	O
JavaScript	B-Language
language	I-Language
syntax	O
.	O
</s>
<s>
Similar	O
in	O
appearance	O
to	O
HTML	B-Language
,	O
JSX	B-Language
provides	O
a	O
way	O
to	O
structure	O
component	O
rendering	O
using	O
syntax	O
familiar	O
to	O
many	O
developers	O
.	O
</s>
<s>
React	B-Application
components	B-Architecture
are	O
typically	O
written	O
using	O
JSX	B-Language
,	O
although	O
they	O
do	O
not	O
have	O
to	O
be	O
(	O
components	B-Architecture
may	O
also	O
be	O
written	O
in	O
pure	O
JavaScript	B-Language
)	O
.	O
</s>
<s>
JSX	B-Language
is	O
similar	O
to	O
another	O
extension	O
syntax	O
created	O
by	O
Facebook	O
for	O
PHP	B-Application
called	O
XHP	B-Language
.	O
</s>
<s>
An	O
example	O
of	O
JSX	B-Language
code	O
:	O
</s>
<s>
The	O
basic	O
architecture	O
of	O
React	B-Application
applies	O
beyond	O
rendering	O
HTML	B-Language
in	O
the	O
browser	O
.	O
</s>
<s>
For	O
example	O
,	O
Facebook	O
has	O
dynamic	O
charts	O
that	O
render	O
to	O
<canvas>	O
tags	O
,	O
and	O
Netflix	O
and	O
PayPal	O
use	O
universal	O
loading	O
to	O
render	O
identical	O
HTML	B-Language
on	O
both	O
the	O
server	O
and	O
client	O
.	O
</s>
<s>
Server-side	O
rendering	O
refers	O
to	O
the	O
process	O
of	O
rendering	O
a	O
client-side	O
JavaScript	B-Language
application	O
on	O
the	O
server	O
,	O
rather	O
than	O
in	O
the	O
browser	O
.	O
</s>
<s>
With	O
server-side	O
rendering	O
,	O
the	O
initial	O
HTML	B-Language
that	O
is	O
sent	O
to	O
the	O
client	O
includes	O
the	O
fully	O
rendered	O
UI	O
of	O
the	O
application	O
.	O
</s>
<s>
This	O
allows	O
the	O
client	O
's	O
browser	O
to	O
display	O
the	O
UI	O
immediately	O
,	O
rather	O
than	O
having	O
to	O
wait	O
for	O
the	O
JavaScript	B-Language
to	O
download	O
and	O
execute	O
before	O
rendering	O
the	O
UI	O
.	O
</s>
<s>
React	B-Application
supports	O
server-side	O
rendering	O
,	O
which	O
allows	O
developers	O
to	O
render	O
React	B-Application
components	B-Architecture
on	O
the	O
server	O
and	O
send	O
the	O
resulting	O
HTML	B-Language
to	O
the	O
client	O
.	O
</s>
<s>
React	B-Application
does	O
not	O
attempt	O
to	O
provide	O
a	O
complete	O
"	O
application	O
library	O
"	O
.	O
</s>
<s>
It	O
is	O
designed	O
specifically	O
for	O
building	O
user	B-Application
interfaces	I-Application
and	O
therefore	O
does	O
not	O
include	O
many	O
of	O
the	O
tools	O
some	O
developers	O
might	O
consider	O
necessary	O
to	O
build	O
an	O
application	O
.	O
</s>
<s>
To	O
support	O
React	B-Application
's	O
concept	O
of	O
unidirectional	O
data	O
flow	O
(	O
which	O
might	O
be	O
contrasted	O
with	O
AngularJS	B-Application
's	O
bidirectional	O
flow	O
)	O
,	O
the	O
Flux	O
architecture	O
was	O
developed	O
as	O
an	O
alternative	O
to	O
the	O
popular	O
model	O
–	O
view	O
–	O
controller	O
architecture	O
.	O
</s>
<s>
When	O
used	O
with	O
React	B-Application
,	O
this	O
propagation	O
is	O
accomplished	O
through	O
component	O
properties	O
.	O
</s>
<s>
Since	O
its	O
conception	O
,	O
Flux	O
has	O
been	O
superseded	O
by	O
libraries	O
such	O
as	O
Redux	B-Language
and	O
MobX	O
.	O
</s>
<s>
Flux	O
can	O
be	O
considered	O
a	O
variant	O
of	O
the	O
observer	B-Language
pattern	I-Language
.	O
</s>
<s>
A	O
React	B-Application
component	O
under	O
the	O
Flux	O
architecture	O
should	O
not	O
directly	O
modify	O
any	O
props	O
passed	O
to	O
it	O
,	O
but	O
should	O
be	O
passed	O
callback	O
functions	O
that	O
create	O
actions	O
which	O
are	O
sent	O
by	O
the	O
dispatcher	O
to	O
modify	O
the	O
store	O
.	O
</s>
<s>
Many	O
implementations	O
of	O
Flux	O
have	O
been	O
created	O
since	O
its	O
inception	O
,	O
perhaps	O
the	O
most	O
well-known	O
being	O
Redux	B-Language
,	O
which	O
features	O
a	O
single	O
store	O
,	O
often	O
called	O
a	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
.	O
</s>
<s>
In	O
February	O
2019	O
,	O
useReducer	O
was	O
introduced	O
as	O
a	O
React	B-Application
hook	O
in	O
the	O
16.8	O
release	O
.	O
</s>
<s>
It	O
provides	O
an	O
API	B-General_Concept
that	O
is	O
consistent	O
with	O
Redux	B-Language
,	O
enabling	O
developers	O
to	O
create	O
Redux-like	O
stores	O
that	O
are	O
local	O
to	O
component	O
states	O
.	O
</s>
<s>
However	O
,	O
major	O
changes	O
to	O
React	B-Application
go	O
through	O
the	O
Future	O
of	O
React	B-Application
repository	O
issues	O
and	O
pull	O
requests	O
.	O
</s>
<s>
This	O
enables	O
the	O
React	B-Application
community	O
to	O
provide	O
feedback	O
on	O
new	O
potential	O
features	O
,	O
experimental	O
APIs	B-General_Concept
and	O
JavaScript	B-Language
syntax	O
improvements	O
.	O
</s>
<s>
React	B-Application
was	O
created	O
by	O
Jordan	O
Walke	O
,	O
a	O
software	O
engineer	O
at	O
Meta	O
,	O
who	O
released	O
an	O
early	O
prototype	O
of	O
React	B-Application
called	O
"	O
FaxJS	O
"	O
.	O
</s>
<s>
He	O
was	O
influenced	O
by	O
XHP	B-Language
,	O
an	O
HTML	B-Language
component	O
library	O
for	O
PHP	B-Application
.	O
</s>
<s>
It	O
was	O
first	O
deployed	O
on	O
Facebook	O
's	O
News	B-Application
Feed	I-Application
in	O
2011	O
and	O
later	O
on	O
Instagram	B-Application
in	O
2012	O
.	O
</s>
<s>
React	B-Application
Native	I-Application
,	O
which	O
enables	O
native	O
Android	B-Application
,	O
iOS	B-Application
,	O
and	O
UWP	B-Device
development	O
with	O
React	B-Application
,	O
was	O
announced	O
at	O
Facebook	O
's	O
React	B-Application
Conf	O
in	O
February	O
2015	O
and	O
open-sourced	O
in	O
March	O
2015	O
.	O
</s>
<s>
On	O
April	O
18	O
,	O
2017	O
,	O
Facebook	O
announced	O
React	B-Application
Fiber	O
,	O
a	O
new	O
set	O
of	O
internal	O
algorithms	O
for	O
rendering	O
,	O
as	O
opposed	O
to	O
React	B-Application
's	O
old	O
rendering	O
algorithm	O
,	O
Stack	O
.	O
</s>
<s>
React	B-Application
Fiber	O
was	O
to	O
become	O
the	O
foundation	O
of	O
any	O
future	O
improvements	O
and	O
feature	O
development	O
of	O
the	O
React	B-Application
library	O
.	O
</s>
<s>
The	O
actual	O
syntax	O
for	O
programming	O
with	O
React	B-Application
does	O
not	O
change	O
;	O
only	O
the	O
way	O
that	O
the	O
syntax	O
is	O
executed	O
has	O
changed	O
.	O
</s>
<s>
React	B-Application
's	O
old	O
rendering	O
system	O
,	O
Stack	O
,	O
was	O
developed	O
at	O
a	O
time	O
when	O
the	O
focus	O
of	O
the	O
system	O
on	O
dynamic	O
change	O
was	O
not	O
understood	O
.	O
</s>
<s>
JavaScript	B-Language
functions	O
and	O
virtual	O
DOM	B-General_Concept
objects	O
are	O
called	O
"	O
fibers	O
"	O
,	O
and	O
each	O
can	O
be	O
operated	O
and	O
updated	O
separately	O
,	O
allowing	O
for	O
smoother	O
on-screen	O
rendering	O
.	O
</s>
<s>
On	O
September	O
26	O
,	O
2017	O
,	O
React	B-Application
16.0	O
was	O
released	O
to	O
the	O
public	O
.	O
</s>
<s>
On	O
August	O
10	O
,	O
2020	O
,	O
the	O
React	B-Application
team	O
announced	O
the	O
first	O
release	O
candidate	O
for	O
React	B-Application
v17.0	O
,	O
notable	O
as	O
the	O
first	O
major	O
release	O
without	O
major	O
changes	O
to	O
the	O
React	B-Application
developer-facing	O
API	B-General_Concept
.	O
</s>
<s>
On	O
March	O
29	O
,	O
2022	O
,	O
React	B-Application
18	O
was	O
released	O
which	O
introduced	O
a	O
new	O
concurrent	O
renderer	O
,	O
automatic	O
batching	O
and	O
support	O
for	O
server	O
side	O
rendering	O
with	O
Suspense	O
.	O
</s>
<s>
+VersionsVersionRelease	O
DateChanges0.3.029	O
May	O
2013Initial	O
Public	O
Release0.4.020	O
July	O
2013Support	O
for	O
comment	O
nodes	O
,	O
Improved	O
server-side	O
rendering	O
APIs	B-General_Concept
,	O
Removed	O
React.autoBind	O
,	O
Support	O
for	O
the	O
key	O
prop	O
,	O
Improvements	O
to	O
forms	O
,	O
Fixed	O
bugs.0.5.020	O
October	O
2013Improve	O
Memory	O
usage	O
,	O
Support	O
for	O
Selection	O
and	O
Composition	O
events	O
,	O
Support	O
for	O
getInitialState	O
and	O
getDefaultProps	O
in	O
mixins	O
,	O
Added	O
React.version	O
and	O
React.isValidClass	O
,	O
Improved	O
compatibility	O
for	O
Windows.0.8.020	O
December	O
2013Added	O
support	O
for	O
rows	O
&	O
cols	O
,	O
defer	O
&	O
async	O
,	O
loop	O
for	O
&	O
,	O
autoCorrect	O
attributes	O
.	O
</s>
<s>
Added	O
onContextMenu	O
events	O
,	O
Upgraded	O
jstransform	O
and	O
esprima-fb	O
tools	O
,	O
Upgraded	O
browserify.0.9.020	O
February	O
2014Added	O
support	O
for	O
crossOrigin	O
,	O
download	O
and	O
hrefLang	O
,	O
mediaGroup	O
and	O
muted	O
,	O
sandbox	O
,	O
seamless	O
,	O
and	O
srcDoc	O
,	O
scope	O
attributes	O
,	O
Added	O
any	O
,	O
arrayOf	O
,	O
component	O
,	O
oneOfType	O
,	O
renderable	O
,	O
shape	O
to	O
React.PropTypes	O
,	O
Added	O
support	O
for	O
onMouseOver	O
and	O
onMouseOut	O
event	O
,	O
Added	O
support	O
for	O
onLoad	O
and	O
onError	O
on	O
elements.0.10.021	O
March	O
2014Added	O
support	O
for	O
srcSet	O
and	O
textAnchor	O
attributes	O
,	O
add	O
update	O
function	O
for	O
immutable	O
data	O
,	O
Ensure	O
all	O
void	O
elements	O
do	O
n't	O
insert	O
a	O
closing	O
tag.0.11.017	O
July	O
2014Improved	O
SVG	O
support	O
,	O
Normalized	O
e.view	O
event	O
,	O
Update	O
$apply	O
command	O
,	O
Added	O
support	O
for	O
namespaces	O
,	O
Added	O
new	O
transformWithDetails	O
API	B-General_Concept
,	O
includes	O
pre-built	O
packages	O
under	O
dist/	O
,	O
MyComponent( )	O
now	O
returns	O
a	O
descriptor	O
,	O
not	O
an	O
instance.0.12.021	O
November	O
2014Added	O
new	O
features	O
Spread	O
operator	O
( {	O
...	O
}	O
)	O
introduced	O
to	O
deprecate	O
this.transferPropsTo	O
,	O
Added	O
support	O
for	O
acceptCharset	O
,	O
classID	O
,	O
manifest	O
HTML	B-Language
attributes	O
,	O
React.addons.batchedUpdates	O
added	O
to	O
API	B-General_Concept
,	O
@jsx	O
React.DOM	O
no	O
longer	O
required	O
,	O
Fixed	O
issues	O
with	O
CSS	O
Transitions.0.13.010	O
March	O
2015Deprecated	O
patterns	O
that	O
warned	O
in	O
0.12	O
no	O
longer	O
work	O
,	O
ref	O
resolution	O
order	O
has	O
changed	O
,	O
Removed	O
properties	O
this._pendingState	O
and	O
this._rootNodeID	O
,	O
Support	O
ES6	B-Language
classes	O
,	O
Added	O
API	B-General_Concept
React.findDOMNode(component )	O
,	O
Support	O
for	O
iterators	O
and	O
immutable-js	O
sequences	O
,	O
Added	O
new	O
features	O
React.addons.createFragment	O
,	O
deprecated	O
React.addons.classSet.0.14.129	O
October	O
2015Added	O
support	O
for	O
srcLang	O
,	O
default	O
,	O
kind	O
attributes	O
,	O
and	O
color	O
attribute	O
,	O
Ensured	O
legacy	O
.props	O
access	O
on	O
DOM	B-General_Concept
nodes	O
,	O
Fixed	O
scryRenderedDOMComponentsWithClass	O
,	O
Added	O
react-dom.js.15.0.07	O
April	O
2016Initial	O
render	O
now	O
uses	O
document.createElement	O
instead	O
of	O
generating	O
HTML	B-Language
,	O
No	O
more	O
extra	O
s	O
,	O
Improved	O
SVG	O
support	O
,	O
is	O
opaque	O
,	O
New	O
deprecations	O
introduced	O
with	O
a	O
warning	O
,	O
Fixed	O
multiple	O
small	O
memory	O
leaks	O
,	O
React	B-Application
DOM	B-General_Concept
now	O
supports	O
the	O
cite	O
and	O
profile	O
HTML	B-Language
attributes	O
and	O
cssFloat	O
,	O
gridRow	O
and	O
gridColumn	O
CSS	O
properties.15.1.020	O
May	O
2016Fix	O
a	O
batching	O
bug	O
,	O
Ensure	O
use	O
of	O
the	O
latest	O
object-assign	O
,	O
Fix	O
regression	O
,	O
Remove	O
use	O
of	O
merge	O
utility	O
,	O
Renamed	O
some	O
modules.15.2.01	O
July	O
2016Include	O
component	O
stack	O
information	O
,	O
Stop	O
validating	O
props	O
at	O
mount	O
time	O
,	O
Add	O
React.PropTypes.symbol	O
,	O
Add	O
onLoad	O
handling	O
to	O
and	O
onError	O
handling	O
to	O
element	O
,	O
Add	O
API	B-General_Concept
,	O
Fix	O
performance	O
regression.15.3.030	O
July	O
2016Add	O
React.PureComponent	O
,	O
Fix	O
issue	O
with	O
nested	O
server	O
rendering	O
,	O
Add	O
xmlns	O
,	O
xmlnsXlink	O
to	O
support	O
SVG	O
attributes	O
and	O
referrerPolicy	O
to	O
HTML	B-Language
attributes	O
,	O
updates	O
React	B-Application
Perf	O
Add-on	O
,	O
Fixed	O
issue	O
with	O
ref.15.3.119	O
August	O
2016Improve	O
performance	O
of	O
development	O
builds	O
,	O
Cleanup	O
internal	O
hooks	O
,	O
Upgrade	O
fbjs	O
,	O
Improve	O
startup	O
time	O
of	O
React	B-Application
,	O
Fix	O
memory	O
leak	O
in	O
server	O
rendering	O
,	O
fix	O
React	B-Application
Test	O
Renderer	O
,	O
Change	O
trackedTouchCount	O
invariant	O
into	O
a	O
console.error.15.4.016	O
November	O
2016React	O
package	O
and	O
browser	O
build	O
no	O
longer	O
includes	O
React	B-Application
DOM	B-General_Concept
,	O
Improved	O
development	O
performance	O
,	O
Fixed	O
occasional	O
test	O
failures	O
,	O
update	O
batchedUpdates	O
API	B-General_Concept
,	O
React	B-Application
Perf	O
,	O
and	O
.15.4.123	O
November	O
2016Restructure	O
variable	O
assignment	O
,	O
Fixed	O
event	O
handling	O
,	O
Fixed	O
compatibility	O
of	O
browser	O
build	O
with	O
AMD	O
environments.15.4.26	O
January	O
2017Fixed	O
build	O
issues	O
,	O
Added	O
missing	O
package	O
dependencies	O
,	O
Improved	O
error	O
messages.15.5.07	O
April	O
2017Added	O
react-dom/test	O
-utils	O
,	O
Removed	O
peerDependencies	O
,	O
Fixed	O
issue	O
with	O
Closure	O
Compiler	O
,	O
Added	O
a	O
deprecation	O
warning	O
for	O
React.createClass	O
and	O
React.PropTypes	O
,	O
Fixed	O
Chrome	O
bug.15.5.411	O
April	O
2017Fix	O
compatibility	O
with	O
Enzyme	O
by	O
exposing	O
batchedUpdates	O
on	O
shallow	O
renderer	O
,	O
Update	O
version	O
of	O
prop-types	O
,	O
Fix	O
react-addons-create-fragment	O
package	O
to	O
include	O
loose-envify	O
transform.15.6.013	O
June	O
2017Add	O
support	O
for	O
CSS	O
variables	O
in	O
style	O
attribute	O
and	O
Grid	O
style	O
properties	O
,	O
Fix	O
AMD	O
support	O
for	O
addons	O
depending	O
on	O
react	B-Application
,	O
Remove	O
unnecessary	O
dependency	O
,	O
Add	O
a	O
deprecation	O
warning	O
for	O
React.createClass	O
and	O
React.DOM	O
factory	O
helpers.16.0.026	O
September	O
2017Improved	O
error	O
handling	O
with	O
introduction	O
of	O
"	O
error	O
boundaries	O
"	O
,	O
React	B-Application
DOM	B-General_Concept
allows	O
passing	O
non-standard	O
attributes	O
,	O
Minor	O
changes	O
to	O
setState	O
behavior	O
,	O
remove	O
react-with-addons.js	O
build	O
,	O
Add	O
React.createClass	O
as	O
create-react-class	O
,	O
React.PropTypes	O
as	O
prop-types	O
,	O
React.DOM	O
as	O
react-dom-factories	O
,	O
changes	O
to	O
the	O
behavior	O
of	O
scheduling	O
and	O
lifecycle	O
methods.16.1.09	O
November	O
2017Discontinuing	O
Bower	O
Releases	O
,	O
Fix	O
an	O
accidental	O
extra	O
global	O
variable	O
in	O
the	O
UMD	O
builds	O
,	O
Fix	O
onMouseEnter	O
and	O
onMouseLeave	O
firing	O
,	O
Fix	O
<textarea>	O
placeholder	O
,	O
Remove	O
unused	O
code	O
,	O
Add	O
a	O
missing	O
package.json	O
dependency	O
,	O
Add	O
support	O
for	O
React	B-Application
DevTools.16.3.029	O
March	O
2018Add	O
a	O
new	O
officially	O
supported	O
context	O
API	B-General_Concept
,	O
Add	O
new	O
packagePrevent	O
an	O
infinite	O
loop	O
when	O
attempting	O
to	O
render	O
portals	O
with	O
SSR	O
,	O
Fix	O
an	O
issue	O
with	O
this.state	O
,	O
Fix	O
an	O
IE/Edge	O
issue.16.3.13	O
April	O
2018Prefix	O
private	O
API	B-General_Concept
,	O
Fix	O
performance	O
regression	O
and	O
error	O
handling	O
bugs	O
in	O
development	O
mode	O
,	O
Add	O
peer	O
dependency	O
,	O
Fix	O
a	O
false	O
positive	O
warning	O
in	O
IE11	O
when	O
using	O
Fragment.16.3.216	O
April	O
2018Fix	O
an	O
IE	O
crash	O
,	O
Fix	O
labels	O
in	O
User	O
Timing	O
measurements	O
,	O
Add	O
a	O
UMD	O
build	O
,	O
Improve	O
performance	O
of	O
unstable_observedBits	O
API	B-General_Concept
with	O
nesting.16.4.024	O
May	O
2018Add	O
support	O
for	O
Pointer	O
Events	O
specification	O
,	O
Add	O
the	O
ability	O
to	O
specify	O
propTypes	O
,	O
Fix	O
reading	O
context	O
,	O
Fix	O
the	O
support	O
,	O
Fix	O
a	O
testInstance.parent	O
crash	O
,	O
Add	O
React.unstable_Profiler	O
component	O
for	O
measuring	O
performance	O
,	O
Change	O
internal	O
event	O
names.16.5.05	O
September	O
2018Add	O
support	O
for	O
React	B-Application
DevTools	O
Profiler	O
,	O
Handle	O
errors	O
in	O
more	O
edge	O
cases	O
gracefully	O
,	O
Add	O
react-dom/profiling	O
,	O
Add	O
onAuxClick	O
event	O
for	O
browsers	O
,	O
Add	O
movementX	O
and	O
movementY	O
fields	O
to	O
mouse	O
events	O
,	O
Add	O
tangentialPressure	O
and	O
twist	O
fields	O
to	O
pointer	O
event.16.6.023	O
October	O
2018Add	O
support	O
for	O
contextType	O
,	O
Support	O
priority	O
levels	O
,	O
continuations	O
,	O
and	O
wrapped	O
callbacks	O
,	O
Improve	O
the	O
fallback	O
mechanism	O
,	O
Fix	O
gray	O
overlay	O
on	O
iOS	B-Application
Safari	O
,	O
Add	O
for	O
code	O
splitting	O
components.16.7.020	O
December	O
2018Fix	O
performance	O
of	O
React.lazy	O
for	O
lazily-loaded	O
components	B-Architecture
,	O
Clear	O
fields	O
on	O
unmount	O
to	O
avoid	O
memory	O
leaks	O
,	O
Fix	O
bug	O
with	O
SSR	O
,	O
Fix	O
a	O
performance	O
regression.16.8.06	O
February	O
2019Add	O
Hooks	O
,	O
Add	O
and	O
for	O
batching	O
updates	O
,	O
Support	O
synchronous	O
thenables	O
passed	O
to	O
React.lazy( )	O
,	O
Improve	O
useReducer	O
Hook	O
lazy	O
initialization	O
API.16.8.627	O
March	O
2019Fix	O
an	O
incorrect	O
bailout	O
in	O
useReducer( )	O
,	O
Fix	O
iframe	O
warnings	O
in	O
Safari	O
DevTools	O
,	O
Warn	O
if	O
contextType	O
is	O
set	O
to	O
Context.Consumer	O
instead	O
of	O
Context	O
,	O
Warn	O
if	O
contextType	O
is	O
set	O
to	O
invalid	O
values.16.9.09	O
August	O
2019Add	O
API	B-General_Concept
for	O
gathering	O
performance	O
measurements	O
programmatically	O
.	O
</s>
<s>
Fix	O
bug	O
when	O
mixing	O
Suspense	O
and	O
error	O
handling.16.10.128	O
September	O
2019Fix	O
regression	O
in	O
Next.js	B-Language
apps	O
by	O
allowing	O
Suspense	O
mismatch	O
during	O
hydration	O
to	O
silently	O
proceed16.10.23	O
October	O
2019Fix	O
regression	O
in	O
react-native-web	O
by	O
restoring	O
order	O
of	O
arguments	O
in	O
event	O
plugin	O
extractors16.11.022	O
October	O
2019Fix	O
mouseenter	O
handlers	O
from	O
firing	O
twice	O
inside	O
nested	O
React	B-Application
containers	O
.	O
</s>
<s>
Remove	O
unstable_createRoot	O
and	O
unstable_createSyncRoot	O
experimental	O
APIs	B-General_Concept
.	O
</s>
<s>
)	O
16.12.014	O
November	O
2019React	O
DOM	B-General_Concept
-	O
Fix	O
passive	O
effects	O
(	O
useEffect	O
)	O
not	O
being	O
fired	O
in	O
a	O
multi-root	O
app	O
.	O
</s>
<s>
React	B-Application
Is	O
-	O
Fix	O
lazy	O
and	O
memo	O
types	O
considered	O
elements	O
instead	O
of	O
components16.13.026	O
February	O
2020Features	O
added	O
in	O
React	B-Application
Concurrent	O
mode	O
.	O
</s>
<s>
Fix	O
regressions	O
in	O
React	B-Application
core	O
library	O
and	O
React	B-Application
Dom.16.13.119	O
March	O
2020Fix	O
bug	O
in	O
legacy	O
mode	O
Suspense	O
.	O
</s>
<s>
Revert	O
warning	O
for	O
cross-component	O
updates	O
that	O
happen	O
inside	O
class	O
render	O
lifecycles16.14.014	O
October	O
2020Add	O
support	O
for	O
the	O
new	O
JSX	B-Language
transform.17.0.020	O
October	O
2020	O
"	O
No	O
New	O
Features	O
"	O
enables	O
gradual	O
React	B-Application
updates	O
from	O
older	O
versions	O
.	O
</s>
<s>
The	O
initial	O
public	O
release	O
of	O
React	B-Application
in	O
May	O
2013	O
used	O
the	O
Apache	B-Application
License	I-Application
2.0	I-Application
.	O
</s>
<s>
In	O
October	O
2014	O
,	O
React	B-Application
0.12.00	O
replaced	O
this	O
with	O
the	O
3-clause	O
BSD	O
license	O
and	O
added	O
a	O
separate	O
PATENTS	O
text	O
file	O
that	O
permits	O
usage	O
of	O
any	O
Facebook	O
patents	O
related	O
to	O
the	O
software:The	O
license	O
granted	O
hereunder	O
will	O
terminate	O
,	O
automatically	O
and	O
without	O
notice	O
,	O
for	O
anyone	O
that	O
makes	O
any	O
claim	O
(	O
including	O
by	O
filing	O
any	O
lawsuit	O
,	O
assertion	O
or	O
other	O
action	O
)	O
alleging	O
(	O
a	O
)	O
direct	O
,	O
indirect	O
,	O
or	O
contributory	O
infringement	O
or	O
inducement	O
to	O
infringe	O
any	O
patent	O
:	O
(	O
i	O
)	O
by	O
Facebook	O
or	O
any	O
of	O
its	O
subsidiaries	O
or	O
affiliates	O
,	O
whether	O
or	O
not	O
such	O
claim	O
is	O
related	O
to	O
the	O
Software	O
,	O
(	O
ii	O
)	O
by	O
any	O
party	O
if	O
such	O
claim	O
arises	O
in	O
whole	O
or	O
in	O
part	O
from	O
any	O
software	O
,	O
product	O
or	O
service	O
of	O
Facebook	O
or	O
any	O
of	O
its	O
subsidiaries	O
or	O
affiliates	O
,	O
whether	O
or	O
not	O
such	O
claim	O
is	O
related	O
to	O
the	O
Software	O
,	O
or	O
(	O
iii	O
)	O
by	O
any	O
party	O
relating	O
to	O
the	O
Software	O
;	O
or	O
(	O
b	O
)	O
that	O
any	O
right	O
in	O
any	O
patent	O
claim	O
of	O
Facebook	O
is	O
invalid	O
or	O
unenforceable.This	O
unconventional	O
clause	O
caused	O
some	O
controversy	O
and	O
debate	O
in	O
the	O
React	B-Application
user	O
community	O
,	O
because	O
it	O
could	O
be	O
interpreted	O
to	O
empower	O
Facebook	O
to	O
revoke	O
the	O
license	O
in	O
many	O
scenarios	O
,	O
for	O
example	O
,	O
if	O
Facebook	O
sues	O
the	O
licensee	O
prompting	O
them	O
to	O
take	O
"	O
other	O
action	O
"	O
by	O
publishing	O
the	O
action	O
on	O
a	O
blog	O
or	O
elsewhere	O
.	O
</s>
<s>
Many	O
expressed	O
concerns	O
that	O
Facebook	O
could	O
unfairly	O
exploit	O
the	O
termination	O
clause	O
or	O
that	O
integrating	O
React	B-Application
into	O
a	O
product	O
might	O
complicate	O
a	O
startup	O
company	O
's	O
future	O
acquisition	O
.	O
</s>
<s>
The	O
Apache	O
Software	O
Foundation	O
considered	O
this	O
licensing	O
arrangement	O
to	O
be	O
incompatible	O
with	O
its	O
licensing	O
policies	O
,	O
as	O
it	O
"	O
passes	O
along	O
risk	O
to	O
downstream	O
consumers	O
of	O
our	O
software	O
imbalanced	O
in	O
favor	O
of	O
the	O
licensor	O
,	O
not	O
the	O
licensee	O
,	O
thereby	O
violating	O
our	O
Apache	O
legal	O
policy	O
of	O
being	O
a	O
universal	O
donor	O
"	O
,	O
and	O
"	O
are	O
not	O
a	O
subset	O
of	O
those	O
found	O
in	O
the	O
[	O
Apache	B-Application
License	I-Application
2.0	I-Application
]	O
,	O
and	O
they	O
cannot	O
be	O
sublicensed	O
as	O
[	O
Apache	B-Application
License	I-Application
2.0	I-Application
]	O
"	O
.	O
</s>
<s>
The	O
following	O
month	O
,	O
WordPress	B-Application
decided	O
to	O
switch	O
its	O
Gutenberg	O
and	O
Calypso	O
projects	O
away	O
from	O
React	B-Application
.	O
</s>
<s>
On	O
September	O
23	O
,	O
2017	O
,	O
Facebook	O
announced	O
that	O
the	O
following	O
week	O
,	O
it	O
would	O
re-license	O
Flow	O
,	O
Jest	B-Language
,	O
React	B-Application
,	O
and	O
Immutable.js	O
under	O
a	O
standard	O
MIT	B-License
License	I-License
;	O
the	O
company	O
stated	O
that	O
React	B-Application
was	O
"	O
the	O
foundation	O
of	O
a	O
broad	O
ecosystem	O
of	O
open	O
source	O
software	O
for	O
the	O
web	O
"	O
,	O
and	O
that	O
they	O
did	O
not	O
want	O
to	O
"	O
hold	O
back	O
forward	O
progress	O
for	O
nontechnical	O
reasons	O
"	O
.	O
</s>
<s>
On	O
September	O
26	O
,	O
2017	O
,	O
React	B-Application
16.0.0	O
was	O
released	O
with	O
the	B-License
MIT	I-License
license	I-License
.	O
</s>
<s>
The	B-License
MIT	I-License
license	I-License
change	O
has	O
also	O
been	O
backported	O
to	O
the	O
15.x	O
release	O
line	O
with	O
React	B-Application
15.6.2	O
.	O
</s>
