What is a side effect in JavaScript?
A side effect is any application state change that is observable outside the called function other than its return value. For example modifying any external...
Categories
- JavaScript 109
- Programming 17
- jQuery 16
- Linux 15
- React 12
- Git 11
- HTTP 10
- ES6 10
- HTML 9
- Java 9
- CSS 9
- Ubuntu 8
- Electronics 5
- XBMC 4
- Web 4
- PDF 4
- Print 4
- Cloud 4
- Raspberry Pi 4
- Firefox 3
- HTML5 3
- CI 3
- SSH 3
- NodeJS 3
- IE 2
- Windows 2
- Hudson 2
- Kids 2
- TV 2
- Music 2
- Mobile 2
- Emacs 2
- Memory 1
- Boxee 1
- Education 1
- 3D 1
- Tools 1
- Ebook 1
- Environment 1
- Performance 1
- Graphics 1
- NoSQL 1
- YouTube 1
- Pandora 1
- JQuery 1
- Linxu 1
- OOP 1
- javascript 1
- Design 1
- Testing 1
- Algorithm 1
- Ruby 1
- Jekyll 1
- Games 1
- Controller 1
- Lego 1
- Robotics 1
- EV3 1
- ES8 1
- Webpack 1
- ReactJS 1
JavaScript
Dependency Injection in JavaScript
Dependency Injection is a pattern where instead of creating or requiring dependencies directly inside a module, we pass them as paramaeters or reference.
Component Composition
Component composition is where a more “specific” component renders a more “generic” one and configures it with props.
Webpack Bundle and Chunk
Bundle Produced from a number of distinct modules, bundles contain the final versions of source files that have already undergone the loading and compilatio...
React server side rendering
React JS , provides ReactDOMServer object which enables to render components to static markup. Typically, it’s used on a Node server.
Migrating from RequireJS to Webpack
Minimal amount of changes in actual code Webpack compiler can understand modules written as ES2015 modules, CommonJS or AMD. Existing code using define() fun...
Webpack
Webpack is module bundler for modern JavaScript applications.
CSS in JS
“CSS in JS” refers to ideas on modularizing CSS , so it helps in maintaing large and medium scale applications easier.
JavaScript Object
An object is a collection of properties. A property is a associate between a name and a value.
JavaScript Array
An array is an ordered list of values that you refer to with a name and an index. JavaScript does not have a explicity array data type. JavaScript provides p...
CORS - Cross-origin resource sharing
CORS is a mechanism that use additional HTTP headers to tell browser to give web application running at one origin access to selected resources from a diffe...
JavaScript Collections
ECMAScript2015(ES6) introduced four new collections Map, Set, WeakMap and WeakSet.
JavaScript Iterators
JavaScript Iterators were added in ECMAScript 2015(ES6). It allows JavaScript objects to specify how custom objects can be used in for...of loops. For a obje...
JavaScript Generators
Generator functions , allow you to define a function whose execution is not continuous. Generator functions are written using the function* syntax.
React Default Prop Values
React Default Props values ensure that the prop will have a value if it was not specified by the parent component.
React PropTypes
React PropTypes help with typechecking on the props for a component. When a invalid value is provided for a prop,a warning will be shown in the JavaScript co...
JavaScript Async and Await
async functions and await are part of ECMAScript 2017(ES8). These features basically act as syntactic sugar on top of promises. They make asynchronous code l...
JavaScript Classes
JavaScript classes were introduced in ECMAScript 2015(ES6). They are primarily syntactical sugar over JavaScript’s existing prototype based inheritance.
JavaScript interview questions
What’s the difference between == and === ?
JavaScript Frameworks
Angular JS
Immutable JS
Much of what makes application development difficult is tracking mutation and maintaining state. Immutability means that once you call that data structure in...
Web Workers
The Web Workers specification defines an API for spawning background scripts in your web application. Web Workers allow you to do things like fire up long-ru...
CSS Object Model (CSSOM)
The CSS Object Model is a set of APIs allowing the manipulation of CSS from JavaScript. It is much like the DOM, but for the CSS rather than the HTML. It all...
Document Object Model (DOM)
The Document Object Model (DOM) is the data representation of the objects that comprise the structure and content of a document on the web.
React Hot Loader
React Hot Loader is a plugin that allows React components to be live reloaded without the loss of state. Basically DOM is re-rendered on each save without do...
React Hooks
Hooks let you use more of React’s features without classes. Hooks embrace functions, but without sacrificing the practical spirit of React.
Two way binding
Two-way data-binding is a mechanism that synchronizes data in a bidirectional way. Two-way binding is a pattern that connects a data model to the UI.
Throttle function
A throttle is a cousin of the debounce, and they both improve the performance of web applications.
Flux pattern
Flux is the application architecture that Facebook uses for building client-side web applications. It complements React’s composable view components by utili...
React Controlled and Uncontrolled Inputs
In HTML, form elements such as input, textarea, and select typically maintain their own state and update it based on user input. In React, mutable state is t...
MVC (Model View Controller) Design Pattern
Design patterns are important to write maintainable and reusable code. A pattern is a reusable solution that can be applied to commonly occurring problems in...
Bubble Sort
The bubble sort makes multiple passes through a list. It compares adjacent items and exchanges those that are out of order. Each pass through the list places...
What is Immediately-Invoked Function Expression (IIFE) ?
An IIFE or Immediately Invoked Function Expression is a function that is gonna get invoked or executed after its creation or declaration. The syntax for crea...
Hoisting in JavaScript
Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope before code execution.
What is Promise Chaining?
A common need is to execute two or more asynchronous operations back to back, where each subsequent operation starts when the previous operation succeeds, wi...
What is AMD, CommonJS
AMD (Asynchronous Module Definition) The AMD module format itself is a proposal for defining modules where both the module and dependencies can be asynchron...
What does not not operator do (!!) ?
It converts Object to boolean. If it was falsey (e.g. 0, null, undefined, etc.), it will be false, otherwise, true.
Difference between Pure and Function React JS component
React.PureComponent is similar to React.Component. The difference between them is that React.Component doesn’t implement shouldComponentUpdate(), but React.P...
What are Curry functions in JavaScript
Currying is a technique of evaluating function with multiple arguments, into sequence of function with single argument. That is, when we turn a function call...
Which one to choose Mocha or Jest
If you have a large project with the need for flexibility and customization then Mocha is probably the choice for you. If you have a smaller project and don’...
What is the difference between Mocha and Chai JS
Mocha provides developers with a base test framework, allowing you to have options as to which assertion, moking and spy libraries you want to use. Chai is o...
Can Jest be used for unit testing Backbone Application?
Yes!! We can unit test Backbone JS applications using Jest
What are first-class functions?
A programming language is said to have first-class functions if it supports passing functions as arguments to other functions, returning them as the values f...
What is a Debounce function?
Debounce function returns a function that as long as it continues to be invoked, will not be triggered. The function will be called after it stops being cal...
What is Universal JavaScript?
“Universal JavaScript” is used to describe JavaScript code that “can execute on the client and the server”.
What are Higher Order Function in JavaScript
Functions that operate on other functions, either by taking them as arguments or by returing them, are called higher order functions.
What is NODE_ENV in Node.js
NODE_ENV is an environment variable made popular by the Express.js framework. It is specifically used to state whethere a particular environment is productio...
What is process.env in Node.js
In Node.js, you can retrieve environment variables by key from process.env object.
Imperative vs Declarative Programming
Declarative programming is more like what you do, or something. Imperative programming is like how you dome something. Declartive programming can be context-...
Factory functions in JavaScript
Factories are simply functions that create objects. You can use factories instead of classes, and factories are simpler than classes and easier to reason abo...
ES6 Destructuring
Destructuring assignment allows you to assign the properties of an array or object to variables using syntax that looks similar to array or object literals. ...
ES6 Rest parameters
The rest parameter syntax allows us to represent an indefinite number of arguments as an array. If you prefix a parameter name with the rest operator (…), th...
ES6 modules
ES6 is the first time JavaScript has built in modules.
What is npm-shrinkwrap ?
npm-shrinkwrap command locks down the versions of a package’s dependencies so that you can control exactly which versions of each dependency will be used whe...
ES6 Spread Syntax
The spread syntax allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) or mu...
What is a React Pure Component ?
If React components render() function renders the same result given the same props and state , you can use PureComponent for a performance boost.
Duck Typing in JavaScript ?
The term duck typing comes from the saying “If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck”.
What is a Promise ?
A promise is an object that may produce a single value some time in the future: either a resolved value, or a reason that it’s not resolved. A promise may be...
JavaScript Closures
Closures are function which ‘remember’ the environment in which they were created. A closure is a combination of a function and the lexical environment withi...
let and const in ES6
ECMAScript 2015 or commonly called as ES6 specification of JavaScript introduced let and const
ES6 Arrow functions
Arrow functions are a more concise syntax for writing function expressions. They were introduced in ECMAScript 2015 (ES6). They are also called as lambda fun...
Difference between ReactJS prop vs state
Props Props are read only. Whether a component is defined as a function or a class, it must never modify its own props. All react component must act like pur...
Core concepts of Redux
Store
What are Functional components in React JS ?
The simplest way to define a component is to write a JavaScript function. The function accepts a single “props” object and returns a React element. Such comp...
What is a pure function ?
A pure function is a function which:
What is JavaScript Event Loop ?
JavaScript code runs single threaded. Javascript has a concurrency model based on an event loop. The event loop is in the heart of Node.js / Javascript - it...
Same origin policy in JavaScript
The same-origin policy restricts how a document or script loaded from one origin can interact with a resource from another origin.
Difference between JS Varaible that is null, undefined, undeclared
undeclared variables don’t even exist undefined variables exist, but don’t have anything assigned to them null variables exist and have null assigned ...
Truth and Falsy in JavaScript
Javascript auto converts any value used in Boolean context (example an if condition) to either true or false. This way of implicitly converting a type is c...
Different ways of creating Objects in JavaScript
Explained below are some of the different ways of creating Objects in JavaScript.
What is prototype and prototype chain in JavaScript
Each JavaScript object has a private property which holds a link to another object called its prototype. That prototype object has a prototype of its own, an...
Constructor in JavaScript
A constructor in JavaScript is a function that is called with the “new” operator.
Difference between scope and context in JavaScript
Difference is scope is function based and context is object based.
JavaScript data types, variables, variable scope, literals, hoisting
Data types JavaScript has six primitive data types, undefined - A variable that has not been assigned a value is of type undefined. null - A special keywo...
JavaScript binding, function apply, function call
In JavaScript, binding is always explicit, and can be easily lost, so a method using “this” will not refer to the proper object in all situations, unless yo...
JavaScript event delegation
JavaScript event delegation is a simple technique by which you add a single event handler to a parent element in order to avoid having to add event handlers ...
JavaScript private public privileged access
Public The members of an object are all public members. There are two ways for putting members in a new object. In Constructor function Container(param) {...
JavaScript function declaration, function expression, Function constructor, Anonymous function
Function declaration function name([param[, param[, ... param]]]) { statements } Example function sum(a, b) { return a + b; } name - The function ...
JavaScript Arguments, Prototype, Constructor, Inheritance
Arguments In every JavaScript function a private variable argument is automatically created, holding array of the arguments passed to the function. Prototy...
Javascript Object oriented programming
*JavaScript is a prototype-based language which contains no class statement. Instead JavaScript uses functions as classes. Defining a class is as easy as def...
Javascript Closures
A closure is a special kind of object that combines two things: a function, and the environment in which that function was created. The environment consists ...
Javascript Module Pattern
Module Pattern - It stays out of the global namespace, provides publicly addressable API methods, and supports protected or “private” data and methods along ...
javascript void(0) for HTML link
To create a HTML link which does nothing when user clicks it, use like below
Referencing variables in setTimeout function - Javascript Closures
Requirement Reference For loop variable i in setTimeout function Wrong way for(var i = 1 ; i <= 10; i++) { console.log('i in for :: ' + i); ...
javascript undefined, null, undefined property, 0, false, ‘’, ==, ===, typeof
== Equals>If the two operands are not of the same type, JavaScript converts the operands then applies strict comparison.
XMLHTTP AJAX abort(), jQuery abort()
I was looking if there was a way to stop an already running AJAX request, like we can stop an http request using browser stop button. Yes there is a way to...
Javascript javadoc - JSDoc
I was looking if there was any standards for writing Javascript API documentation and if there is a tool to parse and generate the document.
jQuery Form serialize method - does not post disabled fields
http://api.jquery.com/serialize/
Validate/Revalidate a single field using jQuery validator
If you have a requirement to just do a single field validation, instead of calling the form validate method which will validate all the fields, then you have...
jQuery JSONP (JSON with padding) - success method not called
Possible reasons for JSONP success method not getting called*In jQuery.getJSON method check if you are adding the
jQuery Validator - Error: $.validator.methods[method] is undefined
Error: $.validator.methods[method] is undefined
what http error code to use for validation error
I was using 500 - Internal Server Error for validation errors, but problem was the application error handler caught this and shows generic error page, which...
jQuery validation plugin , validate only visible fields
Refer this Stack overflow post for the solution
qTip - Excellent jQuery Tooltip plugin
If you are looking for a jQuery tooltip plugin to use for your project, http://craigsworks.com/projects/qtip/ is the right one for you.
Convert JSON Object to String javascript
You can user browser native function JSON.stringify to do this
jQuery Template plugin html in variables
If you pass html content in the template variables, you have to use format to make sure that the html content gets converted into real html elements.
Javascript code equivalent to java i18n MessageFormat
Here is a Stack overflow post with javascript regex solution for this problem.
How to increase clickable area of links
See this A List Apart post - Clickable Region Fix - about this
jQuery not executing script tags in ajax load
This happens when the script code is not correct , or if the script code is a JSON string then the string may not be well formed.
Selecting Dom ID with dot in it through jQuery
I could not select Dom elements with ID having dot character in them. Quick google search gave me this Stack overflow post, which solved my problem.
jQuery Scrollpane plugin
http://jscrollpane.kelvinluck.com/
jQuery Carousel plugin - jCarousel
I am using this plugin in my current project, and its pretty good. The API usage is simple and the output is what we need.
this keyword in javascript
This page neatly explains about “this” keyword
Browser Cross Domain Communication
While building Mashup or building Portals this may be a common development problem. There are 2 ways to solve this 1) Through JSON 2) Through iframe hack - ...
jQuery Grid / Table Data Plugins
Common requirement in any web application development is to show data in Grid / Tabular format.
jQuery AJAX multipart form-data file upload
jQuery Form plugin provides AJAX form upload capabilities . Since XMLHttpRequest does not support upload , the plugin does it neatly using hidden iframe
Online javascript/json beautifier or reverse obfuscator
http://jsbeautifier.org/
Programming
What is a Monorepo?
Monorepo, is a single repository which contains more than one logical project like a web application and its iOS application.
Scratch on Raspberry Pi
"Design Challenge - Remix Jetpack Girl" by ScratchEdTeam is licensed under CC BY 2.0
MVC (Model View Controller) Design Pattern
Design patterns are important to write maintainable and reusable code. A pattern is a reusable solution that can be applied to commonly occurring problems in...
What are first-class functions?
A programming language is said to have first-class functions if it supports passing functions as arguments to other functions, returning them as the values f...
.bash_profile vs .bashrc
.bash_profile is executed for login shells, while .bashrc is executed for interactive non-login shells.
How to delete a Git branch both locally and remotely?
To delete the local branch use: $ git branch -d branch_name
What is Git commit squash?
Git commit squash allows to take a series of commits and squash them down into a single commit with the interactive rebasing tool.
What is semantic commit message?
Semantic commit message is a commit message format which helps to write better commit message.
What is software regression?
A software regression is a software bug which makes a feature to stop functioning as intended after a certain event, for example a system upgrade, system pa...
Imperative vs Declarative Programming
Declarative programming is more like what you do, or something. Imperative programming is like how you dome something. Declartive programming can be context-...
Big O notation
Big O notation is used in computer science to describe the the performance or complexity of an algorithm. Big O specifically describes the the worst case sce...
JavaScript private public privileged access
Public The members of an object are all public members. There are two ways for putting members in a new object. In Constructor function Container(param) {...
Object Oriented Programming
Object Object is an instance of a class. All objects have a state and behavior. Class Class is the blueprint from which individual objects are created I...
Javascript Object oriented programming
*JavaScript is a prototype-based language which contains no class statement. Instead JavaScript uses functions as classes. Defining a class is as easy as def...
Eclipse CRLF and File Encoding
If you are sharing a project which would be edited both in Windows and Unix systems, then its best to set the New text file line delimiter settings for eclip...
Review Board - Code Review tool
Found this Open source code review tool http://www.reviewboard.org/screenshots/ through this Yelp Engineering blog post - http://engineeringblog.yelp.com/...
Coding on Cloud
On reading about Google App Inventor for Android - http://appinventor.googlelabs.com/about/ , I thought of searching the web to find out if there are service...
jQuery
XMLHTTP AJAX abort(), jQuery abort()
I was looking if there was a way to stop an already running AJAX request, like we can stop an http request using browser stop button. Yes there is a way to...
Javascript javadoc - JSDoc
I was looking if there was any standards for writing Javascript API documentation and if there is a tool to parse and generate the document.
jQuery Form serialize method - does not post disabled fields
http://api.jquery.com/serialize/
Validate/Revalidate a single field using jQuery validator
If you have a requirement to just do a single field validation, instead of calling the form validate method which will validate all the fields, then you have...
jQuery JSONP (JSON with padding) - success method not called
Possible reasons for JSONP success method not getting called*In jQuery.getJSON method check if you are adding the
jQuery Validator - Error: $.validator.methods[method] is undefined
Error: $.validator.methods[method] is undefined
jQuery validation plugin , validate only visible fields
Refer this Stack overflow post for the solution
qTip - Excellent jQuery Tooltip plugin
If you are looking for a jQuery tooltip plugin to use for your project, http://craigsworks.com/projects/qtip/ is the right one for you.
jQuery not executing script tags in ajax load
This happens when the script code is not correct , or if the script code is a JSON string then the string may not be well formed.
Selecting Dom ID with dot in it through jQuery
I could not select Dom elements with ID having dot character in them. Quick google search gave me this Stack overflow post, which solved my problem.
jQuery Scrollpane plugin
http://jscrollpane.kelvinluck.com/
jQuery Carousel plugin - jCarousel
I am using this plugin in my current project, and its pretty good. The API usage is simple and the output is what we need.
Browser Cross Domain Communication
While building Mashup or building Portals this may be a common development problem. There are 2 ways to solve this 1) Through JSON 2) Through iframe hack - ...
jQuery Grid / Table Data Plugins
Common requirement in any web application development is to show data in Grid / Tabular format.
jQuery AJAX multipart form-data file upload
jQuery Form plugin provides AJAX form upload capabilities . Since XMLHttpRequest does not support upload , the plugin does it neatly using hidden iframe
jQuery Ajax History/Back Button/Bookmark plugin
If you want to support Back buttons for Ajax or want to give bookmark links for Ajax content, I suggest using jQuery Address plugin
Linux
Configuring the Starship Prompt for Bash
Starship is a minimal, fast, and highly customizable shell prompt written in Rust. It works the same way across Bash, Zsh, Fish, PowerShell, and more, so you...
Windows Subsystem for Linux
The Windows Subsystem for Linux lets developers run a GNU/Linux environment – including most command-line tools, utilities, and applications – directly on Wi...
Connecting to Amazon EC2 Linux instance using PuTTY
EC2 private key file has extension .pem , which cannot be used by PuTTY. So we have to convert .pem to .ppk format which PuTTY accepts. Listing the steps be...
Using Ubuntu GUI remotely using NoMachine or Xming from Windows 7
Solution 1: NoMachine
Running Spotify(Free) for Windows in Ubuntu 11.10 (oneiric) using Wine
*Make sure you have Wine installed http://www.winehq.org/download/ubuntu
Wubi 8.04, errors while installing
While running Wubi.exe got from Ubuntu 8.04.4 LTS (Hardy Heron) download page http://releases.ubuntu.com/8.04/,
Error while upgrading from Ubuntu 10.10 (Maverick Meerkat) to 11.04 (Natty Narwhal)
Got this error while upgrading from Ubuntu 10.10 to 11.04>The disc drive for / is not ready yet or not present. Continue to wait, press S to skip or M for...
Making HP Deskjet 1050 All-in-One printer to work in Ubuntu 10.10
*Go to “HP Linux Imaging and Printing” project in SourceForge.net http://sourceforge.net/projects/hplip/
Installing Kindle For PC on Ubuntu 10.10 Maverick Meerkat
I wanted to use Kindle For PC in Ubuntu 10.10 Maverick Meerkat using “Wine”, but got the below error while running install .exe
Ubuntu Linux command line tool to Convert PDF to Image and from Image to PDF
To convert Convert PDF to Image and from Image to PDF, follow the below steps,*Install ImageMagick - https://help.ubuntu.com/community/ImageMagick
Installing Ubuntu 10.10 Desktop Edition 32 bit from CD
Yesterday while installing Ubuntu 10.10 (Maverick Meerkat) Desktop Edition 32 bit, I faced an error like below -
How to save font settings for PuTTY
I was using PuTTY at a screen resolution of 1600x1200, in which the default font setting caused the text too small to read. So I changed the font to 12px s...
How to start XBMC on Ubuntu Login
Install xmbc standalone scripts sudo apt-get install xbmc-standalone
How to play DVD using XBMC
This was question for which I could not find answer in XBMC documentation/wiki. So thought this might be useful for someone who wants do the same thing. ...
Installing Adobe Digital Editions in Ubuntu
Recently I discovered that my local public library was offering books to download and read in ebook format. Thought to try it out, because ebooks were better...
React
React server side rendering
React JS , provides ReactDOMServer object which enables to render components to static markup. Typically, it’s used on a Node server.
Webpack
Webpack is module bundler for modern JavaScript applications.
CSS in JS
“CSS in JS” refers to ideas on modularizing CSS , so it helps in maintaing large and medium scale applications easier.
React Default Prop Values
React Default Props values ensure that the prop will have a value if it was not specified by the parent component.
React PropTypes
React PropTypes help with typechecking on the props for a component. When a invalid value is provided for a prop,a warning will be shown in the JavaScript co...
React Native
React Native is a JavaScript framework for writing real, natively rendering mobile applications for iOS and Android. It’s based on React, Facebook’s JavaScri...
React Hot Loader
React Hot Loader is a plugin that allows React components to be live reloaded without the loss of state. Basically DOM is re-rendered on each save without do...
React Hooks
Hooks let you use more of React’s features without classes. Hooks embrace functions, but without sacrificing the practical spirit of React.
React Controlled and Uncontrolled Inputs
In HTML, form elements such as input, textarea, and select typically maintain their own state and update it based on user input. In React, mutable state is t...
What is a React Pure Component ?
If React components render() function renders the same result given the same props and state , you can use PureComponent for a performance boost.
Difference between ReactJS prop vs state
Props Props are read only. Whether a component is defined as a function or a class, it must never modify its own props. All react component must act like pur...
What are Functional components in React JS ?
The simplest way to define a component is to write a JavaScript function. The function accepts a single “props” object and returns a React element. Such comp...
Git
What is a Monorepo?
Monorepo, is a single repository which contains more than one logical project like a web application and its iOS application.
How to delete a Git branch both locally and remotely?
To delete the local branch use: $ git branch -d branch_name
How to do undo in Git?
References https://github.com/blog/2019-how-to-undo-almost-anything-with-git
What is Git commit squash?
Git commit squash allows to take a series of commits and squash them down into a single commit with the interactive rebasing tool.
What is Git blame ?
Git blame helps in viewing the line by line revision history for an entire file.
How to write Git commit message
Below are The seven rules of a great Git commit message.
Eclipse CRLF and File Encoding
If you are sharing a project which would be edited both in Windows and Unix systems, then its best to set the New text file line delimiter settings for eclip...
Git GUI checkout single file command
To checkout a single file using Git GUI, go to the Tools menu and add the following command
Git fatal: remote end hung up
The most common reason for “Git fatal: remote end hung up” is due to wrong ssh authentication or some other SSH issue.
Installing Git in CentOS using yum
I wanted to install Git in CentOS release 5.3, but running command
Git pull without password
I wanted to avoid Git asking for password every time I do
HTTP
Nginx Reverse proxy for cross domains
A reverse proxy is a server that sits in front of web servers and forwards client request to those web servers.
CORS - Cross-origin resource sharing
CORS is a mechanism that use additional HTTP headers to tell browser to give web application running at one origin access to selected resources from a diffe...
What is a HttpOnly cookie?
HttpOnly is an additional flag included in Set-Cookie HTTP response header. Using the HttpOnly flag when generating a cookie helps mitigate the risk of clie...
REST Principles
REST stands for Representational State Transfer 5 key principles of REST are -*Give everything a ID Examples http://example.com/orders/2007/11 http://exampl...
what http error code to use for validation error
I was using 500 - Internal Server Error for validation errors, but problem was the application error handler caught this and shows generic error page, which...
Handling cookies with java URLConnection
http://www.hccp.org/java-net-cookie-how-to.html
Firefox addon to build HTTP request
http://stackoverflow.com/questions/725998/are-there-firefox-extension-or-any-other-browser-that-allow-to-send-arbitrary-p
Java update tool jusched.exe occupying HTTP port 80
Today when I started my Tomcat server it was not starting, saying that port 80 was occupied. Then I downloaded this useful tool TCP View - http://technet.m...
| Apache mod_rewrite NE | noescape |
I faced an issue where the URL for example /saved/ was getting rewritten to %2Fsaved%2F, which caused the web application to give 404 error because it expect...
HTTPS and Cache
Does browser cache HTTPS responses? This was a question I had while doing development. Giving below my findings, Did some debugging with Firebug and Fiddle...
ES6
JavaScript Collections
ECMAScript2015(ES6) introduced four new collections Map, Set, WeakMap and WeakSet.
JavaScript Iterators
JavaScript Iterators were added in ECMAScript 2015(ES6). It allows JavaScript objects to specify how custom objects can be used in for...of loops. For a obje...
JavaScript Generators
Generator functions , allow you to define a function whose execution is not continuous. Generator functions are written using the function* syntax.
JavaScript Classes
JavaScript classes were introduced in ECMAScript 2015(ES6). They are primarily syntactical sugar over JavaScript’s existing prototype based inheritance.
ES6 Destructuring
Destructuring assignment allows you to assign the properties of an array or object to variables using syntax that looks similar to array or object literals. ...
ES6 Rest parameters
The rest parameter syntax allows us to represent an indefinite number of arguments as an array. If you prefix a parameter name with the rest operator (…), th...
ES6 modules
ES6 is the first time JavaScript has built in modules.
ES6 Spread Syntax
The spread syntax allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) or mu...
let and const in ES6
ECMAScript 2015 or commonly called as ES6 specification of JavaScript introduced let and const
ES6 Arrow functions
Arrow functions are a more concise syntax for writing function expressions. They were introduced in ECMAScript 2015 (ES6). They are also called as lambda fun...
HTML
Holy Grail CSS Layout
"File:HolyGrail.svg" by David Lark is licensed under CC BY-SA 4.0
View Port
The browser’s viewport is the area of the window in which web content can be seen. This is often not the same size as the rendered page, in which case the br...
Document Object Model (DOM)
The Document Object Model (DOM) is the data representation of the objects that comprise the structure and content of a document on the web.
javascript void(0) for HTML link
To create a HTML link which does nothing when user clicks it, use like below
Difference between Div and Span tag
Good article in the link below about this
How to center a div inside a div
If you need to center a div within another div, here is the solution from Stack overflow post -
How to increase clickable area of links
See this A List Apart post - Clickable Region Fix - about this
HTML5Rocks , Chrome Experiments
http://www.html5rocks.com/
All things HTML5
Found this neat graphic through this Ajaxian blog post
Java
Java HashCode and Equals
Objects that are equal (according to their equals()) must return the same hash code. It’s not required for different objects to return different hash codes.
Java Collections
A collection is a object that groups multiple elements into a single unit.
Apache Ant target execute based on condition
To execute an Ant target based on condition, use the “if” attribute of the target,
Steps to start Tomcat windows service in Debug mode
*Change Directory under Tomcat bin folder C:\Program Files (x86)\Apache Software Foundation\Tomcat 7.0\bin
Handling cookies with java URLConnection
http://www.hccp.org/java-net-cookie-how-to.html
JadClipse - GUI Jad Decompile Eclipse plugin
http://jadclipse.sourceforge.net/wiki/index.php/Main_Page#Download
How to include library manually into maven local repository?
I had a jar file which I wanted to included into classpath of maven compile so that it could compile the project source files. Quick google search landed m...
Java update tool jusched.exe occupying HTTP port 80
Today when I started my Tomcat server it was not starting, saying that port 80 was occupied. Then I downloaded this useful tool TCP View - http://technet.m...
Sun rises in the east
Recently I read a slashdot article - http://it.slashdot.org/story/10/07/28/2121259/Oracles-Java-Company-Change-Breaks-Eclipse about Java 1.6.0_21 release cr...
CSS
CSS in JS
“CSS in JS” refers to ideas on modularizing CSS , so it helps in maintaing large and medium scale applications easier.
Holy Grail CSS Layout
"File:HolyGrail.svg" by David Lark is licensed under CC BY-SA 4.0
CSS Style Guides
CSS style guides are a group of documents that outline the coding style, best practices, and visual design properties (e.g. colors, layout grid dimensions, ...
CSS Frameworks
CSS frameworks provide a basic structure for designing consistent solutions to tackle common recurring issues across front end web development. They provide ...
CSS Object Model (CSSOM)
The CSS Object Model is a set of APIs allowing the manipulation of CSS from JavaScript. It is much like the DOM, but for the CSS rather than the HTML. It all...
What is the difference between CSS word-break vs word-wrap?
overflow-wrap (word-wrap) and word-break behave very similarly and can be used to solve similar problems. word-break is best used with non-English content t...
Responsive vs Adaptive Design
Responsive Design - Responsive websites respond to the browser size at any given point. No matter the browser width, the site adjusts its layout.
Difference between CSS reset and normalize
Normalize.css Preserves useful defaults rather than “unstyling” everything. Corrects some common bugs that are out of scope for reset.css. Doesn’t clu...
How to center a div inside a div
If you need to center a div within another div, here is the solution from Stack overflow post -
Ubuntu
Using Ubuntu GUI remotely using NoMachine or Xming from Windows 7
Solution 1: NoMachine
Running Spotify(Free) for Windows in Ubuntu 11.10 (oneiric) using Wine
*Make sure you have Wine installed http://www.winehq.org/download/ubuntu
Error while upgrading from Ubuntu 10.10 (Maverick Meerkat) to 11.04 (Natty Narwhal)
Got this error while upgrading from Ubuntu 10.10 to 11.04>The disc drive for / is not ready yet or not present. Continue to wait, press S to skip or M for...
Making HP Deskjet 1050 All-in-One printer to work in Ubuntu 10.10
*Go to “HP Linux Imaging and Printing” project in SourceForge.net http://sourceforge.net/projects/hplip/
Installing Kindle For PC on Ubuntu 10.10 Maverick Meerkat
I wanted to use Kindle For PC in Ubuntu 10.10 Maverick Meerkat using “Wine”, but got the below error while running install .exe
Ubuntu Linux command line tool to Convert PDF to Image and from Image to PDF
To convert Convert PDF to Image and from Image to PDF, follow the below steps,*Install ImageMagick - https://help.ubuntu.com/community/ImageMagick
Boxee in Ubuntu 64 bit
Couple of times I wanted to use Boxee in Ubuntu 64 bit, but failed attempting it because there was no official support for it. Recently I found that they ha...
How to start XBMC on Ubuntu Login
Install xmbc standalone scripts sudo apt-get install xbmc-standalone
Electronics
GPIO - General Purpose Input Output
"PI GPIO reference board on a Rasperry Pi Rev 1" by Low Voltage Labs is licensed under CC BY-SA 2.0
Scratch on Raspberry Pi
"Design Challenge - Remix Jetpack Girl" by ScratchEdTeam is licensed under CC BY 2.0
Essential Raspberry Pi accessories
Essential accessories to get started with Raspberry Pi.
What is Raspberry Pi?
The Raspberry Pi is a low cost, credit-card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. It is a capable...
What is a Transistor?
"Various Electronic Components" by mercadoviagens.com is licensed under CC BY 2.0
XBMC
How to setup MCE IR Remote for XBMC
IR Remote model which I am using is “Noah Company MediaGate HA-IR01SV Windows Vista Home Premium and Windows Vista Ultimate MCE Remote Control, 1 Channel IR ...
Boxee in Ubuntu 64 bit
Couple of times I wanted to use Boxee in Ubuntu 64 bit, but failed attempting it because there was no official support for it. Recently I found that they ha...
How to start XBMC on Ubuntu Login
Install xmbc standalone scripts sudo apt-get install xbmc-standalone
How to play DVD using XBMC
This was question for which I could not find answer in XBMC documentation/wiki. So thought this might be useful for someone who wants do the same thing. ...
Web
Common digital image formats
JPEG (Joint Photographic Experts Group)
Internet Explorer min-width CSS property does not work
If the min-width property does not work in Internet Explorer
HTTPS and Cache
Does browser cache HTTPS responses? This was a question I had while doing development. Giving below my findings, Did some debugging with Firebug and Fiddle...
Print to PDF Wikipedia Articles
I wanted to get a Encyclopedia CD, but thought are there any other open source alternatives. Even though I couldn’t find any alternative, I found there was ...
Print on demand
I had a PDF which had about 400 pages which I wanted to print with a low cost solution. I searched internet but couldn’t find any service matching my need, b...
Print to PDF
Frequently I have faced situations where I had to print a page, but I didn’t have a printer. For example say I ordered for a camera on Frys.com, and It give...
Merge PDF
I have had couple of occasions where I had to print more than 1 PDF file, but problem was if I sent each PDF one by one to the printer, the printer prints e...
Print to PDF Wikipedia Articles
I wanted to get a Encyclopedia CD, but thought are there any other open source alternatives. Even though I couldn’t find any alternative, I found there was ...
Print on demand
I had a PDF which had about 400 pages which I wanted to print with a low cost solution. I searched internet but couldn’t find any service matching my need, b...
Print to PDF
Frequently I have faced situations where I had to print a page, but I didn’t have a printer. For example say I ordered for a camera on Frys.com, and It give...
Merge PDF
I have had couple of occasions where I had to print more than 1 PDF file, but problem was if I sent each PDF one by one to the printer, the printer prints e...
Cloud
Connecting to Amazon EC2 Linux instance using PuTTY
EC2 private key file has extension .pem , which cannot be used by PuTTY. So we have to convert .pem to .ppk format which PuTTY accepts. Listing the steps be...
Pogoplug Gets Down to Business
Pogoplug Gets Down to Business.
Coding on Cloud
On reading about Google App Inventor for Android - http://appinventor.googlelabs.com/about/ , I thought of searching the web to find out if there are service...
NoSQL Pioneers Are Driving the Web’s Manifest Destiny (via GigaOM)
I find the classification of NoSQL databases useful, if I am going to use a NoSQL db anytime in future I am going to look at this table.
Raspberry Pi
GPIO - General Purpose Input Output
"PI GPIO reference board on a Rasperry Pi Rev 1" by Low Voltage Labs is licensed under CC BY-SA 2.0
Scratch on Raspberry Pi
"Design Challenge - Remix Jetpack Girl" by ScratchEdTeam is licensed under CC BY 2.0
Essential Raspberry Pi accessories
Essential accessories to get started with Raspberry Pi.
What is Raspberry Pi?
The Raspberry Pi is a low cost, credit-card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. It is a capable...
Firefox
Cooliris Firefox plugin
Cooliris gives a interface which seems more natural for viewing photos or videos instead of clicking next and previous buttons. This interface seems to be si...
Firefox and IE Memory Profiler
For Firefox, there is this addon more details about the tool here - Memory Profiler. But this addon is not available for Firefox 3.6.3, So if you are plan...
Running different versions of Firefox
I was using latest version of Firefox 3.6.3, but wanted to install a add on which works only on Firefox 3.5. But I didn’t want to uninstall my latest Firef...
HTML5
HTML5Rocks , Chrome Experiments
http://www.html5rocks.com/
All things HTML5
Found this neat graphic through this Ajaxian blog post
Does my browser support HTML5 video
I wanted to know if my browser Firefox 3.6.3 supported HTML5 video. Easy solution was to try out the HTML5 video demos provided in this site HTML5video.org
CI
Apache Ant target execute based on condition
To execute an Ant target based on condition, use the “if” attribute of the target,
How to include library manually into maven local repository?
I had a jar file which I wanted to included into classpath of maven compile so that it could compile the project source files. Quick google search landed m...
My Hudson instance occasionally tells me that I have multiple instances running
Do you get this kind of error “Hudson detected that you appear to be running more than one instance of Hudson that share the same home directory”
SSH
Connecting to Amazon EC2 Linux instance using PuTTY
EC2 private key file has extension .pem , which cannot be used by PuTTY. So we have to convert .pem to .ppk format which PuTTY accepts. Listing the steps be...
Setting up an SSH tunnel with PuTTY
Setting up an SSH tunnel with PuTTY
How to save font settings for PuTTY
I was using PuTTY at a screen resolution of 1600x1200, in which the default font setting caused the text too small to read. So I changed the font to 12px s...
NodeJS
What is NODE_ENV in Node.js
NODE_ENV is an environment variable made popular by the Express.js framework. It is specifically used to state whethere a particular environment is productio...
What is process.env in Node.js
In Node.js, you can retrieve environment variables by key from process.env object.
What is npm-shrinkwrap ?
npm-shrinkwrap command locks down the versions of a package’s dependencies so that you can control exactly which versions of each dependency will be used whe...
IE
IE 8 Browser Modes
IE 8 Developer Tools gives a feature called Browser Modes, with which you can check how your web site works and look in IE 7 without having to install IE 7 ....
Firefox and IE Memory Profiler
For Firefox, there is this addon more details about the tool here - Memory Profiler. But this addon is not available for Firefox 3.6.3, So if you are plan...
Windows
Windows Subsystem for Linux
The Windows Subsystem for Linux lets developers run a GNU/Linux environment – including most command-line tools, utilities, and applications – directly on Wi...
Windows 7/Vista/XP/2k Password Recovery / Clear tool
My friend recently bought a Sony Vaio laptop with Windows 7 pre installed. Don’t know what he did, he called me up and said he forgot the password and couldn...
Hudson
My Hudson instance occasionally tells me that I have multiple instances running
Do you get this kind of error “Hudson detected that you appear to be running more than one instance of Hudson that share the same home directory”
Hudson Environmental Variables
If you want to quickly find out the environmental variables available in your Hudson instance go to the following URL **http:///env-vars.html** or [this pa...
Kids
Photo Factory - PBS Parents
http://www.pbs.org/parents/photo/
Free kids fairytale ebooks
Found this website http://www.epubbooks.com/genre/fairy-tales offering free ebooks, while reading this Ajaxian article - http://ajaxian.com/archives/poc-ep...
TV
YouTube leanback
http://www.youtube.com/leanback
Google TV
From what I can understand after seeing the video hosted on http://www.google.com/tv/, it’s a Google search interface for TV channels. Also there is featur...
Music
Running Spotify(Free) for Windows in Ubuntu 11.10 (oneiric) using Wine
*Make sure you have Wine installed http://www.winehq.org/download/ubuntu
How Pandora Grew to Get 60 Million Listeners (via GigaOM)
I am using Pandora in PC either through Boxee or Web Browser, so I can’t comment about using it on Iphone, but why I like and why I think its increasing its ...
Mobile
React Native
React Native is a JavaScript framework for writing real, natively rendering mobile applications for iOS and Android. It’s based on React, Facebook’s JavaScri...
Sync Google contacts with Nokia E63 phone contacts
Follow steps below to sync your Google contacts with Nokia E63 phone contacts.
Emacs
How to search bash command history in Emacs multi term
C-r in Emacs multi term invokes (isearch-backward) command. To search bash command history we can use M-r instead.
How to configure multi term in Emacs to allow login shell
To configure multi term in Emacs to allow login shell
Memory
Firefox and IE Memory Profiler
For Firefox, there is this addon more details about the tool here - Memory Profiler. But this addon is not available for Firefox 3.6.3, So if you are plan...
Boxee
Boxee in Ubuntu 64 bit
Couple of times I wanted to use Boxee in Ubuntu 64 bit, but failed attempting it because there was no official support for it. Recently I found that they ha...
Education
Open source software for Preschool kids
Tux Paint Unique feature for kids is the Coloring Book , where we can load a coloring book type image from the available library of images and then allow...
3D
Roomle - online room planning software
Found this cool online tool - Roomle through Lifehacker
Tools
Open Source Software to count lines of code
I wanted to count the number of lines of code for java /jsp/ javascript etc files in my project. Unix word count (wc) tool could have given me the results wi...
Ebook
Free kids fairytale ebooks
Found this website http://www.epubbooks.com/genre/fairy-tales offering free ebooks, while reading this Ajaxian article - http://ajaxian.com/archives/poc-ep...
Environment
Energy Saving A/C
http://www.nrel.gov/features/20100611_ac.html#nogo A new A/C technology has been invented which will reduce energy consumption by 50 to 90% which is really a...
Performance
Back to Top ↑Graphics
Online Photo editor - Pixlr
http://www.pixlr.com/editor/
NoSQL
NoSQL Pioneers Are Driving the Web’s Manifest Destiny (via GigaOM)
I find the classification of NoSQL databases useful, if I am going to use a NoSQL db anytime in future I am going to look at this table.
YouTube
YouTube Blog: What’s bigger than 1080p? 4K video comes to YouTube
YouTube Blog: What’s bigger than 1080p? 4K video comes to YouTube.
Pandora
How Pandora Grew to Get 60 Million Listeners (via GigaOM)
I am using Pandora in PC either through Boxee or Web Browser, so I can’t comment about using it on Iphone, but why I like and why I think its increasing its ...
JQuery
jQuery Template plugin html in variables
If you pass html content in the template variables, you have to use format to make sure that the html content gets converted into real html elements.
Linxu
How to setup MCE IR Remote for XBMC
IR Remote model which I am using is “Noah Company MediaGate HA-IR01SV Windows Vista Home Premium and Windows Vista Ultimate MCE Remote Control, 1 Channel IR ...
OOP
How to create a class in JavaScript
In JavaScript classes can be created using functions. Let’s see how.
javascript
How to create a class in JavaScript
In JavaScript classes can be created using functions. Let’s see how.
Design
Responsive vs Adaptive Design
Responsive Design - Responsive websites respond to the browser size at any given point. No matter the browser width, the site adjusts its layout.
Testing
What is a Test Fixture ?
A test fixture is a fixed state of a set of objects used as a baseline for running tests. The purpose of test fixture is to ensure that there is a well known...
Algorithm
Bubble Sort
The bubble sort makes multiple passes through a list. It compares adjacent items and exchanges those that are out of order. Each pass through the list places...
Ruby
Jekyll server with Ruby 2.7.0 gives ‘warning Using the last argument as keyword parameters is deprecated’
Running Jekyll local server with Ruby 2.7.0 gives warnings as below,
Jekyll
Jekyll server with Ruby 2.7.0 gives ‘warning Using the last argument as keyword parameters is deprecated’
Running Jekyll local server with Ruby 2.7.0 gives warnings as below,
Games
XInput and DirectInput
"File:Logitech Rumblepad F510, 1.jpg" by Morn is licensed under CC BY-SA 3.0
Controller
XInput and DirectInput
"File:Logitech Rumblepad F510, 1.jpg" by Morn is licensed under CC BY-SA 3.0
Lego
Lego Mindstroms EV3
"'Falcon' Lego Mindstorms EV3 Robot by Kyle Markland" by dluders is licensed under CC BY 2.0
Robotics
Lego Mindstroms EV3
"'Falcon' Lego Mindstorms EV3 Robot by Kyle Markland" by dluders is licensed under CC BY 2.0
EV3
Lego Mindstroms EV3
"'Falcon' Lego Mindstorms EV3 Robot by Kyle Markland" by dluders is licensed under CC BY 2.0
ES8
JavaScript Async and Await
async functions and await are part of ECMAScript 2017(ES8). These features basically act as syntactic sugar on top of promises. They make asynchronous code l...
Webpack
Webpack Bundle and Chunk
Bundle Produced from a number of distinct modules, bundles contain the final versions of source files that have already undergone the loading and compilatio...
ReactJS
Component Composition
Component composition is where a more “specific” component renders a more “generic” one and configures it with props.