What is Node?
Course Overview
Pure Node.js
The history of Node.js
JavaScript and ES2015
Installation and basics
Less important parts of the API
External services
Node is popular!
- Server side framework
- Mobile and IoT
- Desktop applications
- Millions of users
- Largest ecosystem
Node's popularity
This course
- Intermediate Skills
- Advanced Skills
What needs to improve?
- The event-loop
- V8 and the Call Stack
- Sockets
- Event Emitters
- Streams
- Clusters
How well do you know Node.js?
This course
Course Path
- What is Node?
- npm
- Concurrency Model and Event Loop
- Workshop #1
- Node's Event-driven Architecture
- Node for Networking
- Node for Web
- Node's Common Built-in Libraries
- Working with Streams
- Clusters and Child Processes
- Workshop #2
- Express.js
-
Real-time Communication with Node.js
- Testing
-
Workshop #3
-
API Documentation, Automation and Deployment
-
Debugging Node.js In Production
-
Node.js + TypeScript
-
Workshop #4
Architecture:
V8 and libuv
Node VMs
$ node -v
v7.7.4
$ node -p 'process.versions.v8'
5.5.372.42
V8 Feature groups
Shipping
Staged
In progress
--harmony
$ node -p "'Node'.padEnd(8, '*')"
[eval]:1
'Node'.padEnd(8, '*')
^
TypeError: "Node".padEnd is not a function
at [eval]:1:8
at ContextifyScript.Script.runInThisContext (vm.js:23:33)
at Object.runInThisContext (vm.js:95:38)
at Object.<anonymous> ([eval]-wrapper:6:22)
at Module._compile (module.js:571:32)
at Immediate.<anonymous> (bootstrap_node.js:392:29)
at runCallback (timers.js:666:20)
at tryOnImmediate (timers.js:639:5)
at processImmediate [as _immediateCallback] (timers.js:611:5)
$ node --harmony -p "'Node'.padEnd(8, '*')"
Node****
$ node --v8-options | grep "in progress"
--harmony_array_prototype_values (enable "harmony Array.prototype.values" (in progress))
--harmony_function_sent (enable "harmony function.sent" (in progress))
--harmony_sharedarraybuffer (enable "harmony sharedarraybuffer" (in progress))
--harmony_simd (enable "harmony simd" (in progress))
--harmony_do_expressions (enable "harmony do-expressions" (in progress))
--harmony_restrictive_generators (enable "harmony restrictions on generator declarations" (in progress))
--harmony_regexp_named_captures (enable "harmony regexp named captures" (in progress))
--harmony_regexp_property (enable "harmony unicode regexp property classes" (in progress))
--harmony_for_in (enable "harmony for-in syntax" (in progress))
--harmony_trailing_commas (enable "harmony trailing commas in function parameter lists" (in progress))
--harmony_class_fields (enable "harmony public fields in class literals" (in progress))
Node’s CLI and REPL
Read
Eval
Loop
node
> 3 == '3'
true
> var a = 2
undefined
>
>
Array Boolean Date Error
EvalError Function Infinity JSON
Math NaN Number Object
RangeError ReferenceError RegExp String
SyntaxError TypeError URIError decodeURI
decodeURIComponent encodeURI encodeURIComponent eval
isFinite isNaN parseFloat parseInt
undefined
ArrayBuffer Buffer COUNTER_HTTP_CLIENT_REQUEST COUNTER_HTTP_CLIENT_RESPONSE
COUNTER_HTTP_SERVER_REQUEST COUNTER_HTTP_SERVER_RESPONSE COUNTER_NET_SERVER_CONNECTION COUNTER_NET_SERVER_CONNECTION_CLOSE
DTRACE_HTTP_CLIENT_REQUEST DTRACE_HTTP_CLIENT_RESPONSE DTRACE_HTTP_SERVER_REQUEST DTRACE_HTTP_SERVER_RESPONSE
DTRACE_NET_SERVER_CONNECTION DTRACE_NET_STREAM_END DataView Float32Array
Float64Array GLOBAL Int16Array Int32Array
Int8Array Intl Map Promise
Proxy Reflect Set Symbol
Uint16Array Uint32Array Uint8Array Uint8ClampedArray
WeakMap WeakSet _ a
assert buffer child_process clearImmediate
clearInterval clearTimeout cluster console
crypto dgram dns domain
escape events fs global
http https module net
os path process punycode
querystring readline repl require
root setImmediate setInterval setTimeout
stream string_decoder tls tty
unescape url util v8
vm zlib
__defineGetter__ __defineSetter__ __lookupGetter__ __lookupSetter__
__proto__ constructor hasOwnProperty isPrototypeOf
propertyIsEnumerable toLocaleString toString valueOf
>
Autocomplete - Double TAB
> global.
global.__defineGetter__ global.__defineSetter__ global.__lookupGetter__ global.__lookupSetter__
global.__proto__ global.constructor global.hasOwnProperty global.isPrototypeOf
global.propertyIsEnumerable global.toLocaleString global.toString global.valueOf
global.Array global.ArrayBuffer global.Boolean global.Buffer
global.COUNTER_HTTP_CLIENT_REQUEST global.COUNTER_HTTP_CLIENT_RESPONSE global.COUNTER_HTTP_SERVER_REQUEST global.COUNTER_HTTP_SERVER_RESPONSE
global.COUNTER_NET_SERVER_CONNECTION global.COUNTER_NET_SERVER_CONNECTION_CLOSE global.DTRACE_HTTP_CLIENT_REQUEST global.DTRACE_HTTP_CLIENT_RESPONSE
global.DTRACE_HTTP_SERVER_REQUEST global.DTRACE_HTTP_SERVER_RESPONSE global.DTRACE_NET_SERVER_CONNECTION global.DTRACE_NET_STREAM_END
global.DataView global.Date global.Error global.EvalError
global.Float32Array global.Float64Array global.Function global.GLOBAL
global.Infinity global.Int16Array global.Int32Array global.Int8Array
global.Intl global.JSON global.Map global.Math
global.NaN global.Number global.Object global.Promise
global.Proxy global.RangeError global.ReferenceError global.Reflect
global.RegExp global.Set global.String global.Symbol
global.SyntaxError global.TypeError global.URIError global.Uint16Array
global.Uint32Array global.Uint8Array global.Uint8ClampedArray global.WeakMap
global.WeakSet global._ global.a global.assert
global.buffer global.child_process global.clearImmediate global.clearInterval
global.clearTimeout global.cluster global.console global.crypto
global.decodeURI global.decodeURIComponent global.dgram global.dns
global.domain global.encodeURI global.encodeURIComponent global.escape
global.eval global.events global.fs global.global
global.http global.https global.isFinite global.isNaN
global.module global.net global.os global.parseFloat
global.parseInt global.path global.process global.punycode
global.querystring global.readline global.repl global.require
global.root global.setImmediate global.setInterval global.setTimeout
global.stream global.string_decoder global.tls global.tty
global.undefined global.unescape global.url global.util
global.v8 global.vm global.zlib
> global.
Autocomplete - Double TAB
> var arr =[];
undefined
> arr.
arr.__defineGetter__ arr.__defineSetter__ arr.__lookupGetter__ arr.__lookupSetter__ arr.__proto__ arr.constructor arr.hasOwnProperty
arr.isPrototypeOf arr.propertyIsEnumerable arr.toLocaleString arr.toString arr.valueOf
arr.concat arr.copyWithin arr.entries arr.every arr.fill arr.filter arr.find
arr.findIndex arr.forEach arr.includes arr.indexOf arr.join arr.keys arr.lastIndexOf
arr.length arr.map arr.pop arr.push arr.reduce arr.reduceRight arr.reverse
arr.shift arr.slice arr.some arr.sort arr.splice arr.unshift
> arr.
Autocomplete - Double TAB
> _
undefined
> Math.random()
0.34758947986306477
> _
0.34758947986306477
> let r = _
undefined
> r
0.34758947986306477
>
The last result - Underscore
> .
break clear editor exit help load save
> .help
.break Sometimes you get stuck, this gets you out
.clear Alias for .break
.editor Enter editor mode
.exit Exit the repl
.help Print this help message
.load Load JS from a file into the REPL session
.save Save all evaluated commands in this REPL session to a file
Special commands - Dot
const repl = require('repl');
repl.start({
ignoreUndefined: true,
replMode: repl.REPL_MODE_STRICT
});Customize REPL
Customize REPL
Global Objects, Process and Buffer
Array Boolean Date Error
EvalError Function Infinity JSON
Math NaN Number Object
RangeError ReferenceError RegExp String
SyntaxError TypeError URIError decodeURI
decodeURIComponent encodeURI encodeURIComponent eval
isFinite isNaN parseFloat parseInt
undefined
ArrayBuffer Buffer COUNTER_HTTP_CLIENT_REQUEST COUNTER_HTTP_CLIENT_RESPONSE
COUNTER_HTTP_SERVER_REQUEST COUNTER_HTTP_SERVER_RESPONSE COUNTER_NET_SERVER_CONNECTION COUNTER_NET_SERVER_CONNECTION_CLOSE
DTRACE_HTTP_CLIENT_REQUEST DTRACE_HTTP_CLIENT_RESPONSE DTRACE_HTTP_SERVER_REQUEST DTRACE_HTTP_SERVER_RESPONSE
DTRACE_NET_SERVER_CONNECTION DTRACE_NET_STREAM_END DataView Float32Array
Float64Array GLOBAL Int16Array Int32Array
Int8Array Intl Map Promise
Proxy Reflect Set Symbol
Uint16Array Uint32Array Uint8Array Uint8ClampedArray
WeakMap WeakSet _ assert
buffer child_process clearImmediate clearInterval
clearTimeout cluster console crypto
dgram dns domain escape
events fs global http
https module net os
path process punycode querystring
readline repl require root
setImmediate setInterval setTimeout stream
string_decoder tls tty unescape
url util v8 vm
zlib
__defineGetter__ __defineSetter__ __lookupGetter__ __lookupSetter__
__proto__ constructor hasOwnProperty isPrototypeOf
propertyIsEnumerable toLocaleString toString valueOf
console.log(global);
{ DTRACE_NET_SERVER_CONNECTION: [Function],
DTRACE_NET_STREAM_END: [Function],
DTRACE_HTTP_SERVER_REQUEST: [Function],
DTRACE_HTTP_SERVER_RESPONSE: [Function],
DTRACE_HTTP_CLIENT_REQUEST: [Function],
DTRACE_HTTP_CLIENT_RESPONSE: [Function],
COUNTER_NET_SERVER_CONNECTION: [Function],
COUNTER_NET_SERVER_CONNECTION_CLOSE: [Function],
COUNTER_HTTP_SERVER_REQUEST: [Function],
COUNTER_HTTP_SERVER_RESPONSE: [Function],
COUNTER_HTTP_CLIENT_REQUEST: [Function],
COUNTER_HTTP_CLIENT_RESPONSE: [Function],
global: [Circular],
process:
process {
title: 'C:\\Program Files (x86)\\JetBrains\\WebStorm 2017.1\\bin\\runnerw.exe',
version: 'v7.7.4',
moduleLoadList:
[ 'Binding contextify',
'Binding natives',
'NativeModule events',
'Binding config',
'Binding icu',
'NativeModule util',
'Binding uv',
'NativeModule buffer',
'Binding buffer',
'Binding util',
'NativeModule internal/util',
'NativeModule internal/buffer',
'NativeModule timers',
'Binding timer_wrap',
'NativeModule internal/linkedlist',
'NativeModule assert',
'NativeModule internal/process',
'NativeModule internal/process/warning',
'NativeModule internal/process/next_tick',
'NativeModule internal/process/promises',
'NativeModule internal/process/stdio',
'Binding constants',
'NativeModule path',
'NativeModule module',
'NativeModule internal/module',
'NativeModule vm',
'NativeModule fs',
'Binding fs',
'NativeModule stream',
'NativeModule internal/streams/legacy',
'NativeModule _stream_readable',
'NativeModule internal/streams/BufferList',
'NativeModule _stream_writable',
'NativeModule _stream_duplex',
'NativeModule _stream_transform',
'NativeModule _stream_passthrough',
'Binding fs_event_wrap',
'NativeModule internal/fs',
'NativeModule internal/url',
'NativeModule internal/querystring',
'Binding url',
'NativeModule querystring',
'NativeModule os',
'Binding os',
'NativeModule console',
'Binding tty_wrap',
'NativeModule net',
'NativeModule internal/net',
'Binding cares_wrap',
'Binding tcp_wrap',
'Binding pipe_wrap',
'Binding stream_wrap' ],
versions:
{ http_parser: '2.7.0',
node: '7.7.4',
v8: '5.5.372.42',
uv: '1.11.0',
zlib: '1.2.11',
ares: '1.10.1-DEV',
modules: '51',
openssl: '1.0.2k',
icu: '58.2',
unicode: '9.0',
cldr: '30.0.3',
tz: '2016j' },
arch: 'x64',
platform: 'win32',
release:
{ name: 'node',
sourceUrl: 'https://nodejs.org/download/release/v7.7.4/node-v7.7.4.tar.gz',
headersUrl: 'https://nodejs.org/download/release/v7.7.4/node-v7.7.4-headers.tar.gz',
libUrl: 'https://nodejs.org/download/release/v7.7.4/win-x64/node.lib' },
argv:
[ 'C:\\Program Files\\nodejs\\node.exe',
'D:\\projects\\nodejs-training\\module-1\\require\\index2.js' ],
execArgv: [],
env:
{ ALLUSERSPROFILE: 'C:\\ProgramData',
APPDATA: 'C:\\Users\\Shukhratbek_Mamadali\\AppData\\Roaming',
CommonProgramFiles: 'C:\\Program Files\\Common Files',
'CommonProgramFiles(x86)': 'C:\\Program Files (x86)\\Common Files',
CommonProgramW6432: 'C:\\Program Files\\Common Files',
COMPUTERNAME: 'EPBYGOMW0515',
ComSpec: 'C:\\WINDOWS\\system32\\cmd.exe',
DEBUG_COLORS: 'true',
DEBUG_FD: '1',
ELECTRON_NO_ATTACH_CONSOLE: 'true',
FORCE_COLOR: 'true',
FPS_BROWSER_APP_PROFILE_STRING: 'Internet Explorer',
FPS_BROWSER_USER_PROFILE_STRING: 'Default',
GIT_SSH: 'C:\\Program Files\\PuTTY\\plink.exe',
GYP_MSVS_VERSION: '2015',
HOMEDRIVE: 'C:',
HOMEPATH: '\\Users\\Shukhratbek_Mamadali',
LOCALAPPDATA: 'C:\\Users\\Shukhratbek_Mamadali\\AppData\\Local',
LOGONSERVER: '\\\\EVBYGOMSA0003',
MOCHA_COLORS: '1',
NUMBER_OF_PROCESSORS: '4',
OneDrive: 'C:\\Users\\Shukhratbek_Mamadali\\OneDrive',
OS: 'Windows_NT',
Path: 'C:\\Program Files\\Docker\\Docker\\Resources\\bin;C:\\WINDOWS\\system32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem;C:\\WINDOWS\\System32\\WindowsPowerShell\\v1.0\\;C:\\Program Files\\Git\\cmd;C:\\Program Files\\PuTTY\\;C:\\Program Files\\nodejs\\;C:\\Program Files\\OpenVPN\\bin;C:\\HashiCorp\\Vagrant\\bin;C:\\Program Files (x86)\\Windows Kits\\8.1\\Windows Performance Toolkit\\;C:\\Ruby23-x64\\bin;C:\\Users\\Shukhratbek_Mamadali\\AppData\\Local\\Microsoft\\WindowsApps;C:\\Users\\Shukhratbek_Mamadali\\AppData\\Roaming\\npm',
PATHEXT: '.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC;.RB;.RBW',
PROCESSOR_ARCHITECTURE: 'AMD64',
PROCESSOR_IDENTIFIER: 'Intel64 Family 6 Model 78 Stepping 3, GenuineIntel',
PROCESSOR_LEVEL: '6',
PROCESSOR_REVISION: '4e03',
ProgramData: 'C:\\ProgramData',
ProgramFiles: 'C:\\Program Files',
'ProgramFiles(x86)': 'C:\\Program Files (x86)',
ProgramW6432: 'C:\\Program Files',
PSModulePath: 'C:\\Program Files\\WindowsPowerShell\\Modules;C:\\WINDOWS\\system32\\WindowsPowerShell\\v1.0\\Modules',
PUBLIC: 'C:\\Users\\Public',
SESSIONNAME: 'Console',
SSL_CERT_FILE: 'C:\\RailsInstaller\\cacert.pem',
SYNDICATION_CONF: 'config/properties.json',
SystemDrive: 'C:',
SystemRoot: 'C:\\WINDOWS',
TEMP: 'C:\\Users\\SHUKHR~1\\AppData\\Local\\Temp',
TMP: 'C:\\Users\\SHUKHR~1\\AppData\\Local\\Temp',
UATDATA: 'C:\\WINDOWS\\CCM\\UATData\\D9F8C395-CAB8-491d-B8AC-179A1FE1BE77',
USERDNSDOMAIN: 'GOMEL.EPAM.COM',
USERDOMAIN: 'GOMEL',
USERDOMAIN_ROAMINGPROFILE: 'GOMEL',
USERNAME: 'Shukhratbek_Mamadali',
USERPROFILE: 'C:\\Users\\Shukhratbek_Mamadali',
VBOX_MSI_INSTALL_PATH: 'C:\\Program Files\\Oracle\\VirtualBox\\',
VS140COMNTOOLS: 'C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\',
WEB_CONCURRENCY: 'cluster.js',
windir: 'C:\\WINDOWS' },
pid: 800,
features:
{ debug: false,
uv: true,
ipv6: true,
tls_npn: true,
tls_alpn: true,
tls_sni: true,
tls_ocsp: true,
tls: true },
_needImmediateCallback: false,
execPath: 'C:\\Program Files\\nodejs\\node.exe',
debugPort: 5858,
_startProfilerIdleNotifier: [Function: _startProfilerIdleNotifier],
_stopProfilerIdleNotifier: [Function: _stopProfilerIdleNotifier],
_getActiveRequests: [Function: _getActiveRequests],
_getActiveHandles: [Function: _getActiveHandles],
reallyExit: [Function: reallyExit],
abort: [Function: abort],
chdir: [Function: chdir],
cwd: [Function: cwd],
umask: [Function: umask],
_kill: [Function: _kill],
_debugProcess: [Function: _debugProcess],
_debugPause: [Function: _debugPause],
_debugEnd: [Function: _debugEnd],
hrtime: [Function: hrtime],
cpuUsage: [Function: cpuUsage],
dlopen: [Function: dlopen],
uptime: [Function: uptime],
memoryUsage: [Function: memoryUsage],
binding: [Function: binding],
_linkedBinding: [Function: _linkedBinding],
_setupDomainUse: [Function: _setupDomainUse],
_events:
{ warning: [Function],
newListener: [Function],
removeListener: [Function] },
_rawDebug: [Function],
_eventsCount: 3,
domain: null,
_maxListeners: undefined,
_fatalException: [Function],
_exiting: false,
assert: [Function],
config: { target_defaults: [Object], variables: [Object] },
emitWarning: [Function],
nextTick: [Function: nextTick],
_tickCallback: [Function: _tickCallback],
_tickDomainCallback: [Function: _tickDomainCallback],
stdout: [Getter],
stderr: [Getter],
stdin: [Getter],
openStdin: [Function],
exit: [Function],
kill: [Function],
argv0: 'C:\\Program Files\\nodejs\\node.exe',
mainModule:
Module {
id: '.',
exports: {},
parent: null,
filename: 'D:\\projects\\nodejs-training\\module-1\\require\\index2.js',
loaded: false,
children: [],
paths: [Object] } },
Buffer:
{ [Function: Buffer]
poolSize: 8192,
from: [Function],
alloc: [Function],
allocUnsafe: [Function],
allocUnsafeSlow: [Function],
isBuffer: [Function: isBuffer],
compare: [Function: compare],
isEncoding: [Function],
concat: [Function],
byteLength: [Function: byteLength] },
clearImmediate: [Function],
clearInterval: [Function],
clearTimeout: [Function],
setImmediate: [Function],
setInterval: [Function],
setTimeout: [Function],
console: [Getter] }process.versions
process.versions.v8
process.env
process.release.lts
process.stdin
process.stdout buffer
{ Buffer:
{ [Function: Buffer]
poolSize: 8192,
from: [Function],
alloc: [Function],
allocUnsafe: [Function],
allocUnsafeSlow: [Function],
isBuffer: [Function: isBuffer],
compare: [Function: compare],
isEncoding: [Function],
concat: [Function],
byteLength: [Function: byteLength] },
SlowBuffer: [Function: SlowBuffer],
INSPECT_MAX_BYTES: 50,
kMaxLength: 2147483647,
transcode: [Function: transcode] }
require()
require("module")
require("something")
console.log(module);
Module {
id: '.',
exports: {},
parent: null,
filename: 'D:\\projects\\nodejs-training\\module-1\\require\\index.js',
loaded: false,
children: [],
paths:
[ 'D:\\projects\\nodejs-training\\module-1\\require\\node_modules',
'D:\\projects\\nodejs-training\\module-1\\node_modules',
'D:\\projects\\nodejs-training\\node_modules',
'D:\\projects\\node_modules',
'D:\\node_modules' ] }require('find-me');
module.js:472
throw err;
^
Error: Cannot find module 'find-me'
at Function.Module._resolveFilename (module.js:470:15)
at Function.Module._load (module.js:418:25)
at Module.require (module.js:498:17)
at require (internal/module.js:20:19)
at Object.<anonymous> (D:\projects\nodejs-training\module-1\require\index.js:1:63)
at Module._compile (module.js:571:32)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)// $HOME/.node_modules
// $HOME/.node_libraries
// $PREFIX/lib/node// index.js
console.log('In ./index.js');
require('find-me');// ./node_modules/find-me.js
console.log('In ./node_modules/find-me.js');// Terminal
In ./index.js
In ./node_modules/find-me.jsrequire.resolve('find-me');loaded: falsem1 is not loaded yet { id: 'm1', content: [ 1 ] }
{ id: 'm2', content: [ 2, 22, 222 ] }
{ id: 'm1', content: [ 1, 11, 111 ] }// m1.js
exports.id = 'm1';
exports.content = [1];
const m2 = require('./m2');
console.log(m2);
exports.content.push(11);
exports.content.push(111);// m2.js
exports.id = 'm2';
exports.content = [2];
exports.content.push(22);
exports.content.push(222);
const m1 = require('./m1');
console.log('m1 is not loaded yet', m1);// index.js
const m1 = require('./lib/m1');
console.log(m1);Wrapping and Caching Modules
exports.id = 1; // this is ok
exports = {id: 1}; // this is not ok
module.exports = {id: 1}; // this is ok
var g = 42; // local to this filenode
require('module').wrapper
[ '(function (exports, require, module, __filename, __dirname) { ',
'\n});' ]
console.log(arguments);{ '0': {},
'1':
{ [Function: require]
resolve: [Function: resolve],
main:
Module {
id: '.',
exports: {},
parent: null,
filename: 'D:\\projects\\nodejs-training\\module-1\\wrapper.js',
loaded: false,
children: [],
paths: [Object] },
extensions: { '.js': [Function], '.json': [Function], '.node': [Function] },
cache: { 'D:\projects\nodejs-training\module-1\wrapper.js': [Object] } },
'2':
Module {
id: '.',
exports: {},
parent: null,
filename: 'D:\\projects\\nodejs-training\\module-1\\wrapper.js',
loaded: false,
children: [],
paths:
[ 'D:\\projects\\nodejs-training\\module-1\\node_modules',
'D:\\projects\\nodejs-training\\node_modules',
'D:\\projects\\node_modules',
'D:\\node_modules' ] },
'3': 'D:\\projects\\nodejs-training\\module-1\\wrapper.js',
'4': 'D:\\projects\\nodejs-training\\module-1' }require = function() {
return { mocked: true};
};
const fs = require('fs');
console.log(fs);Override require
// printStars.js
const print = (stars, header) => {
console.log('*'.repeat(stars));
console.log(header);
console.log('*'.repeat(stars));
};
if (require.main == module) {
// Running as script
print(process.argv[2], process.argv[3]);
} else {
// Being required
module.exports = print;
}// index.js
const printStars = require('./printStars');
printStars(10, 'Hi!');
// index.js
require('./sample');
require('./sample');Caching
// sample.js
console.log(`
Sample
File
`);console.log(require.cache);Caching
Sample
File
{ 'D:\projects\nodejs-training\module-1\wrapper\index.js':
Module {
id: '.',
exports: {},
parent: null,
filename: 'D:\\projects\\nodejs-training\\module-1\\wrapper\\index.js',
loaded: false,
children: [ [Object] ],
paths:
[ 'D:\\projects\\nodejs-training\\module-1\\wrapper\\node_modules',
'D:\\projects\\nodejs-training\\module-1\\node_modules',
'D:\\projects\\nodejs-training\\node_modules',
'D:\\projects\\node_modules',
'D:\\node_modules' ] },
'D:\projects\nodejs-training\module-1\wrapper\sample.js':
Module {
id: 'D:\\projects\\nodejs-training\\module-1\\wrapper\\sample.js',
exports: {},
parent:
Module {
id: '.',
exports: {},
parent: null,
filename: 'D:\\projects\\nodejs-training\\module-1\\wrapper\\index.js',
loaded: false,
children: [Object],
paths: [Object] },
filename: 'D:\\projects\\nodejs-training\\module-1\\wrapper\\sample.js',
loaded: true,
children: [],
paths:
[ 'D:\\projects\\nodejs-training\\module-1\\wrapper\\node_modules',
'D:\\projects\\nodejs-training\\module-1\\node_modules',
'D:\\projects\\nodejs-training\\node_modules',
'D:\\projects\\node_modules',
'D:\\node_modules' ] } }delete require.cache['D:\projects\nodejs-training\module-1\wrapper\sampls.js'];Delete Cache
// sample.js
module.exports = () => {
console.log(`
Sample
File
`);
};Module multiple execute
// index.js
require('./sample')();
require('./sample')();Hello World!
What is Node?
By Shuhratbek Mamadaliyev
