SEARCH KEYWORD -- NULL safe


  Can a == true && a == false be true in JavaScript?

JavaScript is a weak typed language and it has a loose comparison feature where two objects/values of different type can be compared using == operator. This provides developers great flexibility and confusion at the same time.  Before understanding how == works in JavaScript, can you first answer the question in the post title? Can a == true && a == false be true in JavaScript? Normally, we would think that this expression will always return false since a can be either true or ...

   JAVASCRIPT,COMPARISON,INTERVIEW QUESTION,==     2018-03-25 03:39:43

  Deep clone of JavaScript object

In JavaScript world, it's frequently seen object clone. Normally when creating a clone of an object, it's only the reference being cloned but not all contents. In some scenarioes, it's desired to clone all the content instead of just the reference such that any change made to the cloned object will not change the original object. Differences between shallow clone and deep clone can be as simple as: Shallow clone : Only the object reference is cloned but not the content Deep clone : Clone all co...

   JAAVSCRIPT,DEEP CLONE,DEEP COPY,SHALLOW CLONE,SHALLOW COPY     2016-10-31 00:27:24

  The Greatest Regex Trick Ever (Simplified)

There is a post which is really hot recently which showcased a best ever regular expression trick. In this post, it provides a trick which can be adapted to situations where one wants to match some patterns desired and exclude the patterns undesired. In simple, the trick is : Pattern not desired | (Pattern desired) Then taking the group 1 match of the capturing group of matched. This group will contain the strings matching the desired patterns. Have to say this trick is really neat and brilliant...

   REGULAR EXPRESSION,PROGRAMMING,JAVA     2015-10-01 21:59:05

  What is encryption? Its role in the modern age

“Messages and calls are end-to-end encrypted.” If you are a WhatsApp user, you must have read this statement at the top of chats you open. Now, what does it mean? The statement signifies that all the messages or voice notes shared between users are encrypted, and no one can read or listen in on them. As mostly all of us use messaging apps and emails, information security has become a major concern. Moreover, we don’t know how many digital footprints we leave on the web can be t...

   DATA SECURITY,VPN     2021-01-21 08:04:16

  Modal dialog in Java example code

In Java, we can create modal dialog so that the main JFrame cannot be operated on until the modal dialog is closed. To achieve this, we need to use one class in Java--JDialog. This class can be used to create an modal dialog.Example code : import javax.swing.JDialog; import javax.swing.JLabel; import javax.swing.JPanel; public class Dialog extends JDialog{ public Dialog(){ super(); JPanel panel=new JPanel(); panel.add(new JLabel("Hello dialog")); this.getCont...

   Java,Modal,JFrame,JDialog,Demo,Code     2011-08-18 09:50:27

  Understand unsafe in GoLang

Before going to understand unsafe package in GoLang, the first thing needs to talk about is the pointer in GoLang. If you have a background of C language, you must know what pointer means and its usage. With pointer, you are free to operate any data at memory level which means you have great power, but this means that you have great responsibility as well. That's why it might be considered unsafe in lots of cases. Take a look at a simple example of doubling an integer. package main import "fmt"...

   GOLANG,UNSAFE,ZERO-COPY     2020-03-14 23:18:00

  + operation on JavaScript objects

In JavaScript, there are two types of values: primitive and object. Primitives consist undefined, null, boolean, number and string. Other values such as array and function are objects. When applying + operation on different type of values, there would be three kinds of type conversion. Primitive conversion Number conversion String conversion There three type conversions have corresponding abstract operations in JavaScript: ToPrimitive(), ToNumber(), ToString(). For number additi...

   JAVASCRIPT,PROGRAMMING     2018-10-12 22:19:12

  Why Microsoft chooses Alt+F4 to close a window

For a long time, there is a doubt among lots of Windows users especially those English speaking users, that is why Microsoft chooses Alt+F4 to close a window instead of Alt+Q. Alt+Q is more comfortable to press for many keyboards, also Q represents Quit and it is easier for people to understand. Recently Microsoft answered this doubt. Raymond Chen, longtime Microsoft developer and semi-official Windows historian, said the reason is that not everyone speaks English. It d...

   WINDOWS,MICROSOFT,HISTORY,ALT+F4     2016-02-23 09:56:41

  A plugin to update last_error in Delayed Job

delayed_job is a process based asynchronous task processing gem which can be ran at background. It will fork the specified number of processes to execute the tasks asynchronously. The task status is usually stored in the database so that it can be easily integrated into a Rails application where asynchronous job execution is desired. Normally when a job fails to execute or error occurs, it would save the error into the database with the column last_error. Ideally all these will be handled b...

   RUBY,RUBY ON RAILS,DELAYED JOB,LAST_ERROR     2017-11-18 13:05:49

  How does CSDN dare to use plain text as password?

Recently, the China's largest Chinese IT community website named CSDN leaked its user's account information. Later today CSDN made an announcements to its users on their website. The announcement said that some user account information was leaked and the passwords of the accounts were stored as plain text in their database before 2009, and after 2009, they adopted an encryption algorithm to encrypt user password. They urged all users who registered the account before 2009 to change their passwor...

   Security,Information leak,CSDN,Plain text     2011-12-22 09:10:01

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