<s>
Node.js	B-Language
is	O
a	O
cross-platform	B-Operating_System
,	O
open-source	B-Application
server	O
environment	O
that	O
can	O
run	O
on	O
Windows	B-Application
,	O
Linux	B-Application
,	O
Unix	B-Application
,	O
macOS	B-Application
,	O
and	O
more	O
.	O
</s>
<s>
Node.js	B-Language
is	O
a	O
back-end	B-Architecture
JavaScript	B-Language
runtime	B-Device
environment	I-Device
,	O
runs	O
on	O
the	O
V8	B-Language
JavaScript	I-Language
Engine	I-Language
,	O
and	O
executes	O
JavaScript	B-Language
code	O
outside	O
a	O
web	B-Application
browser	I-Application
.	O
</s>
<s>
Node.js	B-Language
lets	O
developers	O
use	O
JavaScript	B-Language
to	O
write	O
command	O
line	O
tools	O
and	O
for	O
server-side	B-Language
scripting	I-Language
.	O
</s>
<s>
The	O
ability	O
to	O
run	O
JavaScript	B-Language
code	O
on	O
the	O
server	O
is	O
often	O
used	O
to	O
generate	O
dynamic	O
web	O
page	O
content	O
before	O
the	O
page	O
is	O
sent	O
to	O
the	O
user	O
's	O
web	B-Application
browser	I-Application
.	O
</s>
<s>
Consequently	O
,	O
Node.js	B-Language
represents	O
a	O
"	O
JavaScript	B-Language
everywhere	O
"	O
paradigm	O
,	O
unifying	O
web-application	B-Application
development	O
around	O
a	O
single	O
programming	O
language	O
,	O
as	O
opposed	O
to	O
using	O
different	O
languages	O
for	O
the	O
server	O
-	O
versus	O
client-side	O
programming	O
.	O
</s>
<s>
Node.js	B-Language
has	O
an	O
event-driven	B-Application
architecture	I-Application
capable	O
of	O
asynchronous	B-Architecture
I/O	I-Architecture
.	O
</s>
<s>
These	O
design	O
choices	O
aim	O
to	O
optimize	O
throughput	O
and	O
scalability	B-Architecture
in	O
web	B-Application
applications	I-Application
with	O
many	O
input/output	B-General_Concept
operations	O
,	O
as	O
well	O
as	O
for	O
real-time	B-Application
Web	B-Application
applications	I-Application
(	O
e.g.	O
,	O
real-time	B-Protocol
communication	I-Protocol
programs	O
and	O
browser	B-Protocol
games	I-Protocol
)	O
.	O
</s>
<s>
The	O
Node.js	B-Language
distributed	B-Application
development	I-Application
project	O
was	O
previously	O
governed	O
by	O
the	O
Node.js	B-Language
Foundation	O
,	O
and	O
has	O
now	O
merged	O
with	O
the	O
JS	O
Foundation	O
to	O
form	O
the	O
OpenJS	B-Language
Foundation	I-Language
.	O
</s>
<s>
OpenJS	B-Language
Foundation	I-Language
is	O
facilitated	O
by	O
the	B-Operating_System
Linux	I-Operating_System
Foundation	I-Operating_System
's	O
Collaborative	O
Projects	O
program	O
.	O
</s>
<s>
Corporate	O
users	O
of	O
Node.js	B-Language
software	O
include	O
GoDaddy	O
,	O
Groupon	B-Application
,	O
IBM	O
,	O
LinkedIn	B-Application
,	O
Microsoft	O
,	O
Netflix	O
,	O
PayPal	O
,	O
SAP	B-Application
,	O
Walmart	O
,	O
Yahoo	O
!,	O
and	O
Amazon	B-Application
Web	I-Application
Services	I-Application
.	O
</s>
<s>
Node.js	B-Language
was	O
written	O
initially	O
by	O
Ryan	O
Dahl	O
in	O
2009	O
,	O
about	O
thirteen	O
years	O
after	O
the	O
introduction	O
of	O
the	O
first	O
server-side	O
JavaScript	B-Language
environment	O
,	O
Netscape	B-Protocol
's	I-Protocol
LiveWire	O
Pro	O
Web	O
.	O
</s>
<s>
The	O
initial	O
release	O
supported	O
only	O
Linux	B-Application
and	O
Mac	B-Application
OS	I-Application
X	O
.	O
</s>
<s>
Its	O
development	O
and	O
maintenance	O
was	O
led	O
by	O
Dahl	O
and	O
later	O
sponsored	O
by	O
Joyent	B-General_Concept
.	O
</s>
<s>
Dahl	O
criticized	O
the	O
limited	O
possibilities	O
of	O
the	O
most	O
popular	O
web	B-Application
server	I-Application
in	O
2009	O
,	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
,	O
to	O
handle	O
a	O
lot	O
of	O
concurrent	B-Operating_System
connections	O
(	O
up	O
to	O
10,000	O
and	O
more	O
)	O
and	O
the	O
most	O
common	O
way	O
of	O
creating	O
code	O
(	O
sequential	B-Architecture
programming	I-Architecture
)	O
,	O
when	O
code	O
either	O
blocked	O
the	O
entire	O
process	O
or	O
implied	O
multiple	O
execution	O
stacks	O
in	O
the	O
case	O
of	O
simultaneous	O
connections	O
.	O
</s>
<s>
Node.js	B-Language
combined	O
Google	B-Application
's	I-Application
V8	B-Language
JavaScript	I-Language
engine	I-Language
,	O
an	O
event	B-General_Concept
loop	I-General_Concept
,	O
and	O
a	O
low-level	O
I/O	B-General_Concept
API	B-Application
.	O
</s>
<s>
In	O
January	O
2010	O
,	O
a	O
package	B-Application
manager	I-Application
was	O
introduced	O
for	O
the	O
Node.js	B-Language
environment	O
called	O
npm	B-Language
.	O
</s>
<s>
The	O
package	B-Application
manager	I-Application
makes	O
it	O
easier	O
for	O
programmers	O
to	O
publish	O
and	O
share	O
source	O
code	O
of	O
Node.js	B-Language
packages	O
and	O
is	O
designed	O
to	O
simplify	O
installation	O
,	O
updating	O
,	O
and	O
uninstallation	O
of	O
packages	O
.	O
</s>
<s>
In	O
June	O
2011	O
,	O
Microsoft	O
and	O
Joyent	B-General_Concept
implemented	O
a	O
native	O
Windows	B-Application
version	O
of	O
Node.js	B-Language
.	O
</s>
<s>
The	O
first	O
Node.js	B-Language
build	O
supporting	O
Windows	B-Application
was	O
released	O
in	O
July	O
2011	O
.	O
</s>
<s>
In	O
January	O
2012	O
,	O
Dahl	O
stepped	O
aside	O
,	O
promoting	O
coworker	O
and	O
npm	B-Language
creator	O
Isaac	O
Schlueter	O
to	O
manage	O
the	O
project	O
.	O
</s>
<s>
In	O
December	O
2014	O
,	O
Fedor	O
Indutny	O
started	O
io.js	O
,	O
a	O
fork	B-Application
of	O
Node.js	B-Language
.	O
</s>
<s>
Due	O
to	O
the	O
internal	O
conflict	O
over	O
Joyent	B-General_Concept
's	O
governance	O
,	O
io.js	O
was	O
created	O
as	O
an	O
open	O
governance	O
alternative	O
with	O
a	O
separate	O
technical	O
committee	O
.	O
</s>
<s>
Unlike	O
Node.js	B-Language
,	O
the	O
authors	O
planned	O
to	O
keep	O
io.js	O
up-to-date	O
with	O
the	O
latest	O
releases	O
of	O
the	B-Application
Google	I-Application
V8	B-Language
JavaScript	I-Language
engine	I-Language
.	O
</s>
<s>
In	O
February	O
2015	O
,	O
the	O
intent	O
to	O
form	O
a	O
neutral	O
Node.js	B-Language
Foundation	O
was	O
announced	O
.	O
</s>
<s>
By	O
June	O
2015	O
,	O
the	O
Node.js	B-Language
and	O
io.js	O
communities	O
voted	O
to	O
work	O
together	O
under	O
the	O
Node.js	B-Language
Foundation	O
.	O
</s>
<s>
In	O
September	O
2015	O
,	O
Node.js	B-Language
v0.12	O
and	O
io.js	O
v3.3	O
were	O
merged	O
back	O
together	O
into	O
Node	O
v4.0	O
.	O
</s>
<s>
This	O
merge	O
brought	O
V8	B-Language
ES6	O
features	O
into	O
Node.js	B-Language
and	O
a	O
long-term	O
support	O
release	O
cycle	O
.	O
</s>
<s>
As	O
of	O
2016	O
,	O
the	O
io.js	O
website	O
recommends	O
that	O
developers	O
switch	O
back	O
to	O
Node.js	B-Language
and	O
that	O
no	O
further	O
releases	O
of	O
io.js	O
are	O
planned	O
due	O
to	O
the	O
merge	O
.	O
</s>
<s>
In	O
2019	O
,	O
the	O
JS	O
Foundation	O
and	O
Node.js	B-Language
Foundation	O
merged	O
to	O
form	O
the	O
OpenJS	B-Language
Foundation	I-Language
.	O
</s>
<s>
On	O
March	O
15	O
2023	O
,	O
Node.js	B-Language
19.8.1	O
was	O
released	O
.	O
</s>
<s>
Node.js	B-Language
allows	O
the	O
creation	O
of	O
Web	B-Application
servers	I-Application
and	O
networking	O
tools	O
using	O
JavaScript	B-Language
and	O
a	O
collection	O
of	O
"	O
modules	O
"	O
that	O
handle	O
various	O
core	O
functionalities	O
.	O
</s>
<s>
Modules	O
are	O
provided	O
for	O
file	B-Application
system	I-Application
I/O	B-General_Concept
,	O
networking	O
(	O
DNS	B-Application
,	O
HTTP	B-Protocol
,	O
TCP	B-Protocol
,	O
TLS/SSL	B-Protocol
,	O
or	O
UDP	B-Protocol
)	O
,	O
binary	O
data	O
(	O
buffers	O
)	O
,	O
cryptography	O
functions	O
,	O
data	B-Architecture
streams	I-Architecture
,	O
and	O
other	O
core	O
functions	O
.	O
</s>
<s>
Node.js	B-Language
'	O
s	O
modules	O
use	O
an	O
API	B-Application
designed	O
to	O
reduce	O
the	O
complexity	O
of	O
writing	O
server	O
applications	O
.	O
</s>
<s>
JavaScript	B-Language
is	O
the	O
only	O
language	O
that	O
Node.js	B-Language
supports	O
natively	O
,	O
but	O
many	O
compile-to-JS	B-Language
languages	O
are	O
available	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
Node.js	B-Language
applications	O
can	O
be	O
written	O
in	O
CoffeeScript	B-Application
,	O
Dart	B-Language
,	O
TypeScript	B-Language
,	O
ClojureScript	B-Language
and	O
others	O
.	O
</s>
<s>
Node.js	B-Language
is	O
primarily	O
used	O
to	O
build	O
network	O
programs	O
such	O
as	O
Web	B-Application
servers	I-Application
.	O
</s>
<s>
The	O
most	O
significant	O
difference	O
between	O
Node.js	B-Language
and	O
PHP	B-Application
is	O
that	O
most	O
functions	O
in	O
PHP	B-Application
block	B-Architecture
until	O
completion	O
(	O
commands	O
execute	O
only	O
after	O
previous	O
commands	O
finish	O
)	O
,	O
while	O
Node.js	B-Language
functions	O
are	O
non-blocking	B-Architecture
(	O
commands	O
execute	O
concurrently	B-Architecture
or	O
even	O
in	O
parallel	B-Operating_System
,	O
and	O
use	O
callbacks	O
to	O
signal	O
completion	O
or	O
failure	O
)	O
.	O
</s>
<s>
Node.js	B-Language
is	O
officially	O
supported	O
on	O
Linux	B-Application
,	O
and	O
Microsoft	B-Application
Windows	I-Application
8.1	O
and	O
Server	O
2012	O
(	O
and	O
later	O
)	O
,	O
with	O
tier	O
2	O
support	O
for	O
SmartOS	O
and	O
IBM	B-Application
AIX	I-Application
and	O
experimental	O
support	O
for	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
OpenBSD	B-Operating_System
also	O
works	O
,	O
and	O
LTS	O
versions	O
available	O
for	O
IBM	B-Application
i	I-Application
(	O
AS/400	O
)	O
.	O
</s>
<s>
The	O
provided	O
source	O
code	O
may	O
also	O
be	O
built	O
on	O
similar	O
operating	B-General_Concept
systems	I-General_Concept
to	O
those	O
officially	O
supported	O
or	O
be	O
modified	O
by	O
third	O
parties	O
to	O
support	O
others	O
such	O
as	O
NonStop	B-Architecture
OS	I-Architecture
and	O
Unix	B-Application
servers	O
.	O
</s>
<s>
Node.js	B-Language
brings	O
event-driven	B-Application
programming	I-Application
to	O
web	B-Application
servers	I-Application
,	O
enabling	O
development	O
of	O
fast	O
web	B-Application
servers	I-Application
in	O
JavaScript	B-Language
.	O
</s>
<s>
Developers	O
can	O
create	O
scalable	B-Architecture
servers	O
without	O
using	O
threading	B-Operating_System
,	O
by	O
using	O
a	O
simplified	O
model	O
of	O
event-driven	B-Application
programming	I-Application
that	O
uses	O
callbacks	O
to	O
signal	O
the	O
completion	O
of	O
a	O
task	O
.	O
</s>
<s>
Node.js	B-Language
connects	O
the	O
ease	O
of	O
a	O
scripting	O
language	O
(	O
JavaScript	B-Language
)	O
with	O
the	O
power	O
of	O
Unix	B-Application
network	O
programming	O
.	O
</s>
<s>
Node.js	B-Language
was	O
built	O
on	O
top	O
of	O
Google	B-Application
's	I-Application
V8	B-Language
JavaScript	I-Language
engine	I-Language
since	O
it	O
was	O
open-sourced	O
under	O
the	O
BSD	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
It	O
is	O
proficient	O
with	O
internet	O
fundamentals	O
such	O
as	O
HTTP	B-Protocol
,	O
DNS	B-Application
,	O
and	O
TCP	B-Protocol
.	O
</s>
<s>
JavaScript	B-Language
was	O
also	O
a	O
well-known	O
language	O
,	O
making	O
Node.js	B-Language
accessible	O
to	O
the	O
web	B-Operating_System
development	I-Operating_System
community	I-Operating_System
.	O
</s>
<s>
There	O
are	O
thousands	O
of	O
open-source	B-Application
libraries	O
for	O
Node.js	B-Language
,	O
most	O
of	O
them	O
hosted	O
on	O
the	O
npm	B-Language
website	O
.	O
</s>
<s>
There	O
are	O
multiple	O
developer	O
conferences	O
and	O
events	O
that	O
support	O
the	O
Node.js	B-Language
community	O
,	O
including	O
NodeConf	O
,	O
Node	O
Interactive	O
,	O
and	O
Node	O
Summit	O
as	O
well	O
as	O
a	O
number	O
of	O
regional	O
events	O
.	O
</s>
<s>
The	O
open-source	B-Application
community	O
has	O
developed	O
web	B-Application
frameworks	I-Application
to	O
accelerate	O
the	O
development	O
of	O
applications	O
.	O
</s>
<s>
Such	O
frameworks	O
include	O
Connect	O
,	O
Express.js	B-Language
,	O
Socket.IO	B-Language
,	O
Feathers.js	O
,	O
Koa.js	O
,	O
Hapi.js	O
,	O
Sails.js	B-Language
,	O
Meteor	B-Language
,	O
Derby	O
,	O
and	O
many	O
others	O
.	O
</s>
<s>
Various	O
packages	O
have	O
also	O
been	O
created	O
for	O
interfacing	O
with	O
other	O
languages	O
or	O
runtime	B-Device
environments	I-Device
such	O
as	O
Microsoft	O
.NET	O
.	O
</s>
<s>
Modern	O
desktop	O
IDEs	B-Application
provide	O
editing	O
and	O
debugging	O
features	O
specifically	O
for	O
Node.js	B-Language
applications	O
.	O
</s>
<s>
Such	O
IDEs	B-Application
include	O
Atom	B-Application
,	O
Brackets	B-Application
,	O
JetBrains	B-Application
WebStorm	O
,	O
Microsoft	B-Application
Visual	I-Application
Studio	I-Application
(	O
with	O
Node.js	B-Language
Tools	O
for	O
Visual	B-Application
Studio	I-Application
,	O
or	O
TypeScript	B-Language
with	O
Node	O
definitions	O
,	O
)	O
NetBeans	B-Application
,	O
Nodeclipse	B-Language
Enide	O
Studio	O
(	O
Eclipse-based	O
)	O
,	O
and	O
Visual	B-Language
Studio	I-Language
Code	I-Language
.	O
</s>
<s>
Certain	O
online	O
web-based	B-Application
IDEs	B-Application
also	O
support	O
Node.js	B-Language
,	O
such	O
as	O
Codeanywhere	O
,	O
Codenvy	B-Language
,	O
Cloud9	B-Application
IDE	I-Application
,	O
Koding	O
,	O
and	O
the	O
visual	O
flow	O
editor	O
in	O
Node-RED	B-Device
.	O
</s>
<s>
Node.js	B-Language
is	O
supported	O
across	O
a	O
number	O
of	O
cloud-hosting	O
platforms	O
like	O
Jelastic	B-General_Concept
,	O
Google	B-General_Concept
Cloud	I-General_Concept
Platform	I-General_Concept
,	O
AWS	B-Application
Elastic	O
Beanstalk	O
,	O
Joyent	B-General_Concept
and	O
others	O
.	O
</s>
<s>
New	O
major	O
releases	O
of	O
Node.js	B-Language
are	O
cut	O
from	O
the	O
GitHub	B-Application
main	O
branch	O
every	O
six	O
months	O
.	O
</s>
<s>
The	O
LTS	O
Working	O
Group	O
manages	O
strategy	O
and	O
policy	O
in	O
collaboration	O
with	O
the	O
Technical	O
Steering	O
Committee	O
of	O
the	O
Node.js	B-Language
Foundation	O
.	O
</s>
<s>
Node.js	B-Language
is	O
a	O
JavaScript	B-Language
runtime	B-Device
environment	I-Device
that	O
processes	O
incoming	O
requests	O
in	O
a	O
loop	O
,	O
called	O
the	O
event	B-General_Concept
loop	I-General_Concept
.	O
</s>
<s>
Node.js	B-Language
uses	O
libuv	B-Language
under	O
the	O
hood	O
to	O
handle	O
asynchronous	O
events	O
.	O
</s>
<s>
Libuv	B-Language
is	O
an	O
abstraction	O
layer	O
for	O
network	O
and	O
file	B-Application
system	I-Application
functionality	O
on	O
both	O
Windows	B-Application
and	O
POSIX-based	O
systems	O
such	O
as	O
Linux	B-Application
,	O
macOS	B-Application
,	O
OSS	O
on	O
NonStop	B-Architecture
,	O
and	O
Unix	B-Application
.	O
</s>
<s>
Node.js	B-Language
operates	O
on	O
a	O
single-thread	B-Operating_System
event	B-General_Concept
loop	I-General_Concept
,	O
using	O
non-blocking	B-Architecture
I/O	I-Architecture
calls	O
,	O
allowing	O
it	O
to	O
support	O
tens	O
of	O
thousands	O
of	O
concurrent	B-Operating_System
connections	O
without	O
incurring	O
the	O
cost	O
of	O
thread	B-Operating_System
context	B-Operating_System
switching	I-Operating_System
.	O
</s>
<s>
The	O
design	O
of	O
sharing	O
a	O
single	B-Operating_System
thread	I-Operating_System
among	O
all	O
the	O
requests	O
that	O
use	O
the	O
observer	B-Language
pattern	I-Language
is	O
intended	O
for	O
building	O
highly	O
concurrent	B-Operating_System
applications	O
,	O
where	O
any	O
function	O
performing	O
I/O	B-General_Concept
must	O
use	O
a	O
callback	O
.	O
</s>
<s>
To	O
accommodate	O
the	O
single-threaded	B-Operating_System
event	B-General_Concept
loop	I-General_Concept
,	O
Node.js	B-Language
uses	O
the	O
libuv	B-Language
library	O
—	O
which	O
,	O
in	O
turn	O
,	O
uses	O
a	O
fixed-sized	O
thread	B-Operating_System
pool	O
that	O
handles	O
some	O
of	O
the	O
non-blocking	B-Architecture
asynchronous	B-Architecture
I/O	I-Architecture
operations	O
.	O
</s>
<s>
A	O
thread	B-Operating_System
pool	O
handles	O
the	O
execution	O
of	O
parallel	B-Operating_System
tasks	O
in	O
Node.js	B-Language
.	O
</s>
<s>
The	O
main	O
thread	B-Operating_System
function	O
call	O
posts	O
tasks	O
to	O
the	O
shared	O
task	O
queue	O
,	O
which	O
threads	B-Operating_System
in	O
the	O
thread	B-Operating_System
pool	O
pull	O
and	O
execute	O
.	O
</s>
<s>
Inherently	O
non-blocking	B-Architecture
system	O
functions	O
such	O
as	O
networking	O
translate	O
to	O
kernel-side	O
non-blocking	B-Architecture
sockets	O
,	O
while	O
inherently	O
blocking	O
system	O
functions	O
such	O
as	O
file	O
I/O	B-General_Concept
run	O
in	O
a	O
blocking	O
way	O
on	O
their	O
own	O
threads	B-Operating_System
.	O
</s>
<s>
When	O
a	O
thread	B-Operating_System
in	O
the	O
thread	B-Operating_System
pool	O
completes	O
a	O
task	O
,	O
it	O
informs	O
the	O
main	O
thread	B-Operating_System
of	O
this	O
,	O
which	O
in	O
turn	O
,	O
wakes	O
up	O
and	O
executes	O
the	O
registered	O
callback	O
.	O
</s>
<s>
A	O
downside	O
of	O
this	O
single-threaded	B-Operating_System
approach	O
is	O
that	O
Node.js	B-Language
does	O
not	O
allow	O
vertical	O
scaling	B-Architecture
by	O
increasing	O
the	O
number	O
of	O
CPU	B-Architecture
cores	I-Architecture
of	O
the	O
machine	O
it	O
is	O
running	O
on	O
without	O
using	O
an	O
additional	O
module	O
,	O
such	O
as	O
cluster	O
,	O
StrongLoop	O
Process	O
Manager	O
,	O
or	O
pm2	O
.	O
</s>
<s>
However	O
,	O
developers	O
can	O
increase	O
the	O
default	O
number	O
of	O
threads	B-Operating_System
in	O
the	O
libuv	B-Language
thread	B-Operating_System
pool	O
.	O
</s>
<s>
The	O
server	O
operating	B-General_Concept
system	I-General_Concept
(	O
OS	O
)	O
is	O
likely	O
to	O
distribute	O
these	O
threads	B-Operating_System
across	O
multiple	O
cores	O
.	O
</s>
<s>
V8	B-Language
is	O
the	O
JavaScript	B-Language
execution	O
engine	O
which	O
was	O
initially	O
built	O
for	O
Google	B-Application
Chrome	I-Application
.	O
</s>
<s>
It	O
was	O
then	O
open-sourced	O
by	O
Google	B-Application
in	O
2008	O
.	O
</s>
<s>
Written	O
in	O
C++	B-Language
,	O
V8	B-Language
compiles	O
JavaScript	B-Language
source	O
code	O
to	O
native	O
machine	O
code	O
at	O
runtime	O
.	O
</s>
<s>
npm	B-Language
is	O
the	O
pre-installed	O
package	B-Application
manager	I-Application
for	O
the	O
Node.js	B-Language
server	O
platform	O
.	O
</s>
<s>
It	O
installs	O
Node.js	B-Language
programs	O
from	O
the	O
,	O
organizing	O
the	O
installation	O
and	O
management	O
of	O
third-party	O
Node.js	B-Language
programs	O
.	O
</s>
<s>
Packages	O
in	O
the	O
npm	B-Language
registry	O
can	O
range	O
from	O
simple	O
helper	O
libraries	O
such	O
as	O
Lodash	B-Language
to	O
task	O
runners	O
such	O
as	O
Grunt	B-Language
.	O
</s>
<s>
Node.js	B-Language
can	O
be	O
combined	O
with	O
a	O
browser	B-Application
with	O
a	O
site	O
,	O
a	O
database	O
that	O
supports	O
JSON	B-General_Concept
data	O
(	O
such	O
as	O
Postgres	B-Application
,	O
MongoDB	B-Application
,	O
or	O
CouchDB	B-Application
)	O
and	O
JSON	B-General_Concept
for	O
a	O
unified	O
JavaScript	B-Language
development	O
stack	O
.	O
</s>
<s>
With	O
the	O
adaptation	O
of	O
what	O
were	O
essentially	O
server-side	O
development	O
patterns	O
such	O
as	O
MVC	O
,	O
MVP	O
,	O
MVVM	O
,	O
etc.	O
,	O
Node.js	B-Language
allows	O
the	O
reuse	O
of	O
the	O
same	O
model	O
and	O
service	O
interface	O
between	O
client	O
side	O
and	O
server	O
side	O
.	O
</s>
<s>
Node.js	B-Language
registers	O
with	O
the	O
operating	B-General_Concept
system	I-General_Concept
so	O
the	O
OS	O
notifies	O
it	O
of	O
connections	O
and	O
issues	O
a	O
callback	O
.	O
</s>
<s>
Within	O
the	O
Node.js	B-Language
runtime	O
,	O
each	O
connection	O
is	O
a	O
small	O
heap	B-Application
allocation	I-Application
.	O
</s>
<s>
Traditionally	O
,	O
relatively	O
heavyweight	O
OS	O
processes	O
or	O
threads	B-Operating_System
handled	O
each	O
connection	O
.	O
</s>
<s>
Node.js	B-Language
uses	O
an	O
event	B-General_Concept
loop	I-General_Concept
for	O
scalability	B-Architecture
,	O
instead	O
of	O
processes	O
or	O
threads	B-Operating_System
.	O
</s>
<s>
In	O
contrast	O
to	O
other	O
event-driven	O
servers	O
,	O
Node.js	B-Language
'	O
s	O
event	B-General_Concept
loop	I-General_Concept
does	O
not	O
need	O
to	O
be	O
called	O
explicitly	O
.	O
</s>
<s>
Instead	O
,	O
callbacks	O
are	O
defined	O
,	O
and	O
the	O
server	O
automatically	O
enters	O
the	O
event	B-General_Concept
loop	I-General_Concept
at	O
the	O
end	O
of	O
the	O
callback	O
definition	O
.	O
</s>
<s>
Node.js	B-Language
exits	O
the	O
event	B-General_Concept
loop	I-General_Concept
when	O
there	O
are	O
no	O
further	O
callbacks	O
to	O
be	O
performed	O
.	O
</s>
<s>
Node.js	B-Language
supports	O
WebAssembly	B-Language
and	O
as	O
of	O
Node	O
14	O
has	O
experimental	O
support	O
of	O
WASI	O
,	O
the	O
WebAssembly	B-Language
System	O
Interface	O
.	O
</s>
<s>
Node.js	B-Language
provides	O
a	O
way	O
to	O
create	O
"	O
add-ons	O
"	O
via	O
a	O
C-based	O
API	B-Application
called	O
N-API	O
,	O
which	O
can	O
be	O
used	O
to	O
produce	O
loadable	O
(	O
importable	O
)	O
.node	O
modules	O
from	O
source	O
code	O
written	O
in	O
C/C	O
++	O
.	O
</s>
<s>
The	O
implementation	O
of	O
the	O
N-API	O
relies	O
on	O
internal	O
C/C	O
++	O
Node.js	B-Language
and	O
V8	B-Language
objects	O
requiring	O
users	O
to	B-Application
import	I-Application
(	O
#include	B-Language
)	O
Node.js	B-Language
specific	O
headers	B-Language
into	O
their	O
native	O
source	O
code	O
.	O
</s>
<s>
As	O
the	O
Node.js	B-Language
API	B-Application
is	O
subject	O
to	O
breaking	O
changes	O
at	O
a	O
binary	O
level	O
,	O
modules	O
have	O
to	O
be	O
built	O
and	O
shipped	O
against	O
specific	O
Node.js	B-Language
versions	O
to	O
work	O
properly	O
.	O
</s>
<s>
To	O
address	O
the	O
issue	O
,	O
third	O
parties	O
have	O
introduced	O
open-sourced	O
С/С	O
++	O
wrappers	O
on	O
top	O
of	O
the	O
API	B-Application
that	O
partially	O
alleviate	O
the	O
problem	O
.	O
</s>
<s>
Even	O
though	O
the	O
core	O
functionality	O
of	O
Node.js	B-Language
resides	O
in	O
a	O
JavaScript	B-Language
built-in	O
library	O
,	O
modules	O
written	O
in	O
C++	B-Language
can	O
be	O
used	O
to	O
enhance	O
capabilities	O
and	O
to	O
improve	O
performance	O
of	O
applications	O
.	O
</s>
<s>
In	O
order	O
to	O
produce	O
such	O
modules	O
one	O
needs	O
to	O
have	O
an	O
appropriate	O
C++	B-Language
compiler	O
and	O
necessary	O
headers	B-Language
(	O
the	O
latter	O
are	O
typically	O
shipped	O
with	O
Node.js	B-Language
itself	O
)	O
,	O
e.g.	O
,	O
gcc	B-Application
,	O
clang	B-Application
or	O
MSVC++	B-Application
.	O
</s>
<s>
The	O
N-API	O
is	O
similar	O
to	O
Java	B-Language
Native	I-Language
Interface	I-Language
.	O
</s>
<s>
In	O
2015	O
,	O
various	O
branches	O
of	O
the	O
greater	O
Node.js	B-Language
community	O
began	O
working	O
under	O
the	O
vendor-neutral	O
Node.js	B-Language
Foundation	O
.	O
</s>
<s>
The	O
stated	O
purpose	O
of	O
the	O
organization	O
"	O
is	O
to	O
enable	O
widespread	O
adoption	O
and	O
help	O
accelerate	O
development	O
of	O
Node.js	B-Language
and	O
other	O
related	O
modules	O
through	O
an	O
open	O
governance	O
model	O
that	O
encourages	O
participation	O
,	O
technical	O
contribution	O
,	O
and	O
a	O
framework	O
for	O
long-term	O
stewardship	O
by	O
an	O
ecosystem	O
invested	O
in	O
Node.js	B-Language
'	O
success.	O
"	O
</s>
<s>
The	O
Node.js	B-Language
Foundation	O
Technical	O
Steering	O
Committee	O
(	O
TSC	O
)	O
is	O
the	O
technical	O
governing	O
body	O
of	O
the	O
Node.js	B-Language
Foundation	O
.	O
</s>
<s>
The	O
TSC	O
is	O
responsible	O
for	O
the	O
core	O
Node.js	B-Language
repo	O
as	O
well	O
as	O
dependent	O
and	O
adjacent	O
projects	O
.	O
</s>
<s>
Other	O
current	O
groups	O
include	O
Website	O
,	O
Streams	O
,	O
Build	O
,	O
Diagnostics	O
,	O
i18n	O
,	O
Evangelism	O
,	O
Docker	O
,	O
Addon	O
API	B-Application
,	O
Benchmarking	O
,	O
Post-mortem	O
,	O
Intl	O
,	O
Documentation	O
,	O
and	O
Testing	O
.	O
</s>
