Since hosting is the default behavior, all functions in JavaScript are hosted in the Creation phase. That’s why we can actually call a function before declaring it.

customFunc();

 function customFunc(){
     let a = 77;
     let b = 4;
     let sum = a + b;
     console.log('Sum : ' + sum) 
 }

The reason for working is for JavaScript default behavior in the Creation phase. Here are some points for convenience:

• The arguments list of the arguments that are passed to the function is created
• The code scans all the functions and each function is stored in a variable object that usually points to the function.
• Then it looks for the declarations of the code variables. And undefined sets the property for each declared variable .

Then the code goes to the execution phase and the line-by-line code is executed according to the execution context.

And that is why since function declaration is earlier in the creation phase and the function call is executed in execution phase, we can use it even before declaring function.

But function expressions will not work this way. Because in function expressions we store our functions in a variable. And that variable undefinedis set as the creation phase . The original function is executed later, so calling the function before declare in the function expression will show the error as it is not a function. Because it’s not really a function right now, just a variable.

 miew();

 var miewVar = function(){
     console.log('Miew is calling')
 }

Similarly, we can use a variable before declaring it. If you use a variable before declaring it undefined because of the Creation phase, it will not show any error, but it will show that variable undefined as it is set in Creation Phase .

console.log('Value of Miew: ' + miew);
var miew = 10

But if you have never declared that variable later, you will want to use it:

console.log('Value of C: ' + miewC);

So hopefully this time, there is a clear idea about hosting. However, for good practice it is not advisable to use a function before declaring it. But there’s definitely a lot of work to be done to understand how JavaScript works within the scene. In some situations, it may be helpful to have such a technique.

The post The concept of hoisting in JavaScript first appeared on Bipon's Diary.

JavaScript is usually run in an environment. Often it may be our most widely used browser, or another application program such as Node JS .

Now from where this JavaScript is run, there is also a JavaScript engine (Google V8 Engine, Spider Monkey, JavaScript Core etc…) whose function is to execute this JavaScript code. Browsers use JavaScript to make JavaScript run. For example, Google Chrome uses Google V8 engine, Firefox uses Spider-Manki / Rihano, Internet Explorer and Edge servers use the engine, and Safari uses JavaScript-core / Nitro (JavaScript has many engines, see here for full reference ).

Now this JavaScript code executes in several steps and runs.

Code > Parser > Convert to machine code > code runs

Here, the code passes through the parser first. Here the syntax error is usually checked. If a syntax error is found, then the error is thrown from here. And if all the syntax is done, then a data structure called Abstract Syntax Tree is created.

The next step is to convert this code into machine code, which our computer can actually understand. And finally our code is run.

Now why do you have to cross such steps before running a code? Yes, our computer does not understand anything but the machine code. Whatever language we write in code, it must be converted to machine code, or our computer may not understand it.

Execution Context and Execution Stack

It is very important to have clear ideas about Execution Context and Execution Stack. There are many trick issues in JavaScript that are difficult to understand unless you can understand exactly the Execution Context and the Execution Stack.

Execution Context:

By default Javascript executes global context. Unlike some other languages, no space functions are executed. And JavaScript’s Global Execution Context is a browser windowobject. Declaring a global variable or assigning it to an windowobject is the same

let bGlobal = 77;

Now I can see if it is window inside:bGlobal

window.bGlobal

Then you see that this seam bGlobalshows the value of your declared

bGlobal === window.bGlobal //true

That means two things are the same. So windowit is the same thing to declare a global variable or assign it to an object.

However, if your environment is not a browser, then this Global Execution Context may be different depending on the environment. For example, Node JS’s Global Execution Context is an globalobject. Depending on the environment it may change.

Execution context is discussed in more detail later.

Execution Stack:

We’ll use an example to get a clear idea about Execution Stack in JavaScript and see how those codes are executed.

function A(){
    let a = ' call from a';
    B();
    console.log('Hey', name + a);
}
function B(){
    let b = ' call from b';
    C();
    console.log('Hey', name +  b)
}
function C(){
    let c = ' call from c';
    console.log('Hey', name + c)
}
A();

If you run this code above, you will see how it runs:

The last ones are coming before and the first ones are later. How does it look random? Yes here we need to understand how the execution stack works. So only then will we have a clear idea of ​​how this code ran. First notice this diagram below:

Here the number codes will be executed according to the serial number. And the diagram on the right is the Basically Execution Stack. If you have no idea about the stack data structure, then the stack is a structure where the first in-out system is maintained. This means that there will be only one way to get data out, and whenever a data is extracted it can be extracted from the top. If you have several glass plates stacked on top of one, then if you want to take a plate, you have to take the top plate first, otherwise you will not be able to take it down or you will still have an accident. The plate that you place at the end of the stack should be taken if you want to take a plate on the data structure system, since this plate is on top of you. And the plate you put first will be the bottom,

Now when our code is number 1 it is assigned to the namevariable Bipon. Then only the function definitions go one by one A(), then B()and finally into the C()execution stack on the global execution context. Nothing will be excluded from inside the function as we have not called any of the functions yet.

Then we A()call the function at number 5 . It will now be positioned on the global execution context in the first execution stack and will now A()start executing the code from within. Now with a variable at number 1, some data is assigned there. But again another function B()is called at number 5 . So now Execution Stack A A()will have another new execution context B()on it and now B()the code will start executing from within. Now here also some data has been assigned to a new variable in number 1. Again another function called number 7 C()is called. So now another execution context C()will be found in the execution stack and now C()the code will start executing from within. Now C()Inside number 1 again, some new data is assigned with a new variable. And the console is logged in the next line which will now show on your console. So the log here is the first thing you see in your output. Now C()execute is over and it will move away. So now the execution context will go B()as it is now at the top of the execution stack. Now B()inside the console log of the number 12 will be printed on the output and so you will see this as the output in the second position. Now the same way B(), the last one and the execution stack will be gone. Now the execution stack will be at the top A(). So now A()it will be executed.A()Console logs located at number 5 will be printed at the output and this function will be finished and removed from the execution stack. And so you can see the output here. This is how the execution stack works in JavaScript. And so we see output like this.

Details on Execution Context:

It is very important to know the details of the execution context. You may have seen in JavaScript that you can call before you define a function and that code will work perfectly.

miew();
function miew() {
 console.log('Miew');
}

This code will work fine if you run it all together.

Or you can use a variable before defining it (before defining it will show the value undefined, no error).

console.log(miew);
var miew = 'Hello World!';

Output will come like this but no error will come

undefined

What causes it? Yes, that’s why we need to have a more in-depth knowledge of execution context so you can understand why it works.

When a function is called, there are two stages:

2. Creation phase

2. Execution Phase

2. Creation Phase: In Creation Phase, the variable object is created first. Then the scope chain is created.

What happens in the creation phase directly in Bengal:

• The arguments list of the arguments that are passed to the function is created
• The code scans all the functions and each function is stored in a variable object that usually points to the function.
• Then it looks for the declarations of the code variables. And undefinedsets the property for each declared variable .

2. Execution Phase: Then the code is executed in this phase. In the case of code execution, the code execution is executed by executing the context. This is why calling a function before defining it works fine. If you use any other variable before declaring it undefined is set as a value and no error shows.

Reference Source : JS Essentials: The JavaScript Engine , Execution Context , Understanding the “this” Keyword in JavaScript , Behind the Scene

The post Behind the Scene in JavaScript first appeared on Bipon's Diary.

Resume ready

Before applying for relocation offer, you must first prepare yourself. You can prepare yourself in many ways. You can prepare yourself based on what technology is going on in the market, what is demanded. You can earn a few professional certifications. However, if you do not prepare yourself, if you do not present yourself in your resume or CV, then there will be no profit. Even referring someone you know will reduce your chances of being shortlisted.

A few days ago I shared some resume tips for juniors on Facebook. I thought I’d write it down here.

• Name Capitalization Incorrect : The first thing you should read when watching a CV is the eye. Correctly writing the name is not just a CV, mail body, cover letter, email account name is always important. Many people see all the lowercase or all the capital case names. Without sufficient reason or style, such writing is inappropriate.
• Non-alignment of font sizes of different sections : Many see the name on the CV written in the normal font (usually 3 or 4), but they have given the font size to enter the project name and description. They also look very bad. A document should not use more than 2-5 sizes. At the same time, there is no need to bolt unnecessarily. Even if there is a consistency. For example, all year or project years can be italicized. Or all company names can be bolded.
• Miscellaneous Technologies Names : Javascript, Django, java, php, mysql, html, openGL, UBUNTU, MAC OS all have incorrect capitalization. If anyone works for 5 years with a technology, then misspelling will not be accepted. On top of that, the string case is a very important thing.
• Sample Term Release Online : / where I can utilize my skills and potential efficiently, / / ​​I have strong management skill /, / I can work under pressure / Term like these are very well known. As well as working in a project or company, the manager or Timlid will understand after six months or a year how much stress or how much pressure you can take. So even though it may be a little thoughtful, it should be time to think about the object or the summary part. And of course not exactly copying from anyone.
• Copying Others’ CV / Resume Format : Nowadays everyone has a CV / Resume. So, it should not be the same format for everyone. For example, the CV of an entrepreneur or a product manager’s CV, and not a graphics designer’s or a multimedia expert’s CV. So it would be best not to blindly imitate. And imitating it is good to follow it with wisdom. As a senior engineer who has been working in the market for 5 years, the reason why he claims 5/5 skill in PHP / Java may not be the same for everyone. So it’s foolish to claim yourself a 4/5 star by comparing it with him.
• Online portfolio: Nowadays everyone has blogs, websites. Or even if these are not GitHub, LinkedIn. It is seen that a few days before sending the CV, GitHub opened the repo and uploaded the same project on the same day and gave it a link. It’s good in one direction. The problem is, if you do not maintain the project, or have no documentation or screenshots of the project, the project will not work. And recruiters don’t even have time to check inside your code. So if you project try to write README beautifully. You can also give a sample command / screenshot. And yes, don’t build a repository with binary files, object files, APK / IPK files. Whether for security or for alchemy, no one will take down your binary and install it. Try publishing on Sourceforge / Play Store / App Store. And if there is no project, So no need to just give GitHub links. It can cause unnecessary upset.
• Not counting margins, alignments, padding : Many people do not maintain the format properly while making the CV. Then work with the text box. And the textbox may not match the original margin of the document. As a result, the writing is bent aside. Or the 9th Ward has gone to the next page. Or, as many people have seen in writing educational backgrounds, Sal, Varsity’s name, CGPA, has written these similar columns. As a result, the name of Varsity has become 2-5 lines. However, CGPA is currently available with 20% of the available pages. These mistakes can be fixed with a little effort.
• PDF / docx / zip not just sending PDFs: Usually the most common document in PDF format is. Then if you want a recruiter, or have a form function, you can provide a dock file. However, many times, only the docx file was sent. This can also be a cause for annoyance because the latest Microsoft Office may not be on everyone’s PC or all the designs can be randomized to convert the document. Many can be seen as a hardy mustard. Zips over PDF and sends. They just cause resentment.
• Understand the difference between the name of the company and the technologyOn many CVs, it is written in either Oracle Expert, or Windows XP / Ten Expert, or Linux Expert. Most companies have multiple products. For example, if I say Oracle, will I understand the Oracle database, or understand Java, or understand MySQL? Again Linux, however, has many sections like Networking, Security, Applications, Embedded, Infrastructure. Many people see this in HTML, CSS, Expert. Now HTML, CSS is the pre-Choo framework in the market. If there is a specific framework then it should be named Mansion. In the same way, there are lots of things on the Windows platform including C Sharp, WPF, .NET, ASP.NET, Driver Development, MFC. Expert on Windows XP or 8 means I can also assume that you are an expert to setup. Haha And yes But not all that IDE can do. So being familiar with JetBrains or VS means that you won’t always be caught up in Expert. So it’s nice to be very specific.
• Attending Seminars and Courses : Many may disagree with me on this point. It is almost like I saw CVT taking part in a robotics or LICT course or seminar. Well, when I see a CV like this, I skip the seminar section. It is not true that anyone will ever become a good programmer if they attend seminars or bootcamps. But yes, if anyone can go to a seminar or bootcamp to build a portfolio of something they can learn, then it is definitely worth it. So for the seminar I attended the 3 solid project without having to write the type 1 solid project that has been Maintained, it is good to have such thing in CV.

The point is, make your resume such that, at a glance, the recruiter understands what you are expecting or where your potentials are strongest. This is why a resume is good for one to two pages. It is best not to do anything so that recruiters are not disturbed. And yes, give your contact number correctly, especially your name, phone number, email and home address so that it doesn’t go wrong. Because later on all your contracts, visa applications, bank accounts, etc. will be created under these names.

Given the interview

If you like referring your resume or applying for a relocation offer, you will receive an interview call from HR or relocated companies. Usually these interviews are done in a few steps. The first step can be a simple phone call (Skype or Hangouts), the next step will be two technical interviews where the senior engineers of the company will verify you. If they give you the green signal you will be taken to the CEO or those in the lead position. They will examine your non-technical issues, such as your leadership, how you set up a job, How to get work done affecting others. It will also be verified as a human being there. Finally if you are called from HR then you will be shortlisted. Basically at this level you will be asked questions like when will you be able to win a salary So do not neglect any step. There are some things to keep in mind when giving an interview.

• Understand correctly during the interview. Your timezone may differ from company to country. So set a time mutually. If you can, then keep your direction flexible as it will take you to the working hours of the company. You will prepare accordingly.
• Install useful apps (Skype or Google Hangouts) when interviewing online. Keep good internet connection ready. You can keep the mobile data ready so that the connection is gone when the connection is gone.
• If there is a video interview, please wear a formal dress. At the same time keep your background clean (if homeless). Never give interviews outside the home (on the ground, on the terrace, in restaurants). It’s really good to have someone unwanted in the room while you’re online.
• If you do not want to use mobile phone for video call, you can buy webcam.
• Be as relaxed as possible during the interview. Answer exactly what the question will be. Explain if you know, or skip if you don’t know. Don’t pretend not to know. And answer as needed. We want to say more than everything. It would be better to skip this habit.
• Say words, thank yous, etc. as per your need. If you do not understand, please ask again.
• If you can keep HR in the mail at the end of the interview then it will be easy for you to follow up.

In the next phase I will talk about how to negotiate with the company on salaries and other benefits. Be good everyone

Next Post Relocation in Malaysia – Dealing with Companies and Passing Employment

Bengali Article

The post Relocation in Malaysia – Resume Preparation and Interview first appeared on Bipon's Diary.

1. Relocation in Malaysia – Resume Preparation and Interview
2. Relocation in Malaysia – Bid negotiations and employment passes with the company
3. Relocation in Malaysia – Applying for a Visa
4. Relocation in Malaysia – Last minute preparation
5. Relocation in Malaysia – Immigration
6. Relocation in Malaysia – Lifestyle Tips

Bengali Article

The post Relocation Guide to Malaysia first appeared on Bipon's Diary.

If the arrow function is:

 const customAsyncCode = async() => {      
     // Asynchronous Codes    
} 

This is how you can identify asynchronous code in your function. This time you have to identify the original asynchronous codes one by one and tell Javascript that this is my promise that it cannot go to the next instruction until it is solved. Before that we will need a promiss, right? Yes, let me start with a promise:

      const a1 = new Promise((resolve, reject) => {
        setTimeout(() => {
          if(true){
            resolve('a 1 resolved');
          }else{
            reject('a 1 error');
          }
        }, 3000)
      })

Now we will handle this promise inside an asynchronous function. That is why I will call our Promise talk inside with an asynchronous identifying function. Now this is where we awaitneed the keyword. With this we will identify our Promise so that this Promise does not go to the next instruction until completed:

const promiseHandle = async() => {
        const data = await a1;
        console.log(data);
      }
      promiseHandle();

Notice here that I just printed the data from our premise in the next line. Yes, here asyncis awaitthe magic of it. It helps our asynchronous code behave asynchronously so that we no longer have to call the callback. We can retrieve data with a single line-by-line instruction. Now if you call this function you will see our desired data:

promiseHandle()

Now you will see that your console is printed on the next line of console log. If you have trouble understanding it, then setTimeout()you can extend the time and test it yourself by working code synchronously:

Now if the promise is rejected? Yes then try…catchwe can handle this rejection or error with our previous block. Before that, our promise to create another such thing:

      const a1Rejection = new Promise((resolve, reject) => {
        setTimeout(() => {
          if(true){
            reject('a 1 error');
          }else{
            resolve('a 1 resolved');
          }
        }, 3000)
      })

Now we async awaitwill create our function. But before we can take data from this promise, we have to try…catchput the whole thing inside the block. And with that catchblock we can access our error message:

     const promiseErrorHandle = async() => {
        try{
          const data = await a1Rejection;
          console.log(data);
        }catch(err){
          console.log(err);
        }
      }

promiseErrorHandle();

An alternative method to handle more than one promise , now we want to promise more than they can handle synchronously. Suppose we have two promise:

   const a1 = new Promise((resolve, reject) => {
        setTimeout(() => {
          if(true){
            resolve('a 1 resolved');
          }else{
            reject('a 1 error');
          }
        }, 3000)
      })

Another one

     const a2 = new Promise((resolve, reject) => {
        setTimeout(() => {
            if(true) {
              resolve('a 2 Resolved');
            } else {
              reject('a 2 Error');
            }
        }, 3000)
      })

Now here’s something to understand. If we Promise.alluse it, let’s see if it returns:

console.log('Return all Promise :', Promise.all([a1, a2]))

That means the promise also returns:

So with that we can easily handle multiple promises like this:

 const handleMultiplePromise = async() => {
        const data = await Promise.all([a1, a2]);
        console.log(data);
}

Well then how come their data? Yes the data will come in the same array size as we have seen before. Now call the function:

handleMultiplePromise();

The post JavaScript: async and await first appeared on Bipon's Diary.

The task of the Promise is to handle such asynchronous operations. Now we are running the operation on a remote server, but until data arrives we cannot say that operation will not succeed or fail. And basically, the promise works to handle these. In most cases, we do not have to create our own promises. We handle Just Promise. The basic structure of the promise is that the library we work with will be implemented from the system. We have to handle just Promise. But I’ll also look at how we can create our own promise here.

    let bb = new Promise((resolve, reject) => {
      let a = 1 + 1;
      if(a == 2){
        resolve('Success man!')
      }else{
        reject('Faild man!')
      }
    })

    bb.then((message) => {
      console.log('Get', message)
    }).catch((message) =>{
      console.log('Get', message)
    })

Promise takes two arguments, resolveand reject.

Handle Promise:

Now we will handle whether the Promise has succeeded or failed. In that case, if the Promise is successful then we can chain our bb function and .then()give a callback function here, which resolvewill run if the Promise is successful or otherwise:

    bb.then((message) => {
      console.log('Get', message)
    }).catch((message) =>{
      console.log('Get', message)
    })

Callback

After that trueargument resolve, our callback will be triggered by the promise :

  bb.then((message) => {
      console.log('Get', message)
    })

And if the promise is rejected, then we need .catch()to handle it in another chain operation with a callback function. Now we do not know whether the operation will succeed or fail. In that case, we .then()have to .catch()keep both. .catch()If for any reason we will run reject:

.catch((message) =>{
      console.log('Get', message)
    })

The arguments falsegiven here rejectwill be from the promise . And so  catchthe callback will run inside the block after the operation is finished :

  let bb = new Promise((resolve, reject) => {
      let a = 1 + 2;
      if(a == 2){
        resolve('Success man!')
      }else{
        reject('Faild man!')
      }
    })

    bb.then((message) => {
      console.log('Get', message)
    }).catch((message) =>{
      console.log('Get', message)
    })

The bbfunction that we first returned the Promise here, the creation of the Promise, in most cases, does not require us to write. Rather, the system we use to exchange data, or use the library, is coded as a part of how to do resolveor not do rejectit. In most cases, the promise of our return .then(), and .catch()with the handle. The callbacks that are used inside, in most cases, the data we want from our remote server comes as arguments. We can access those arguments from within a callback.

Handling Multiple Promises: At times, we may have to handle multiple promos. For example, we have two premises:

      const a1 = new Promise((resolve, reject) => {
        setTimeout(() => {
          if(true){
            resolve('a 1 resolved');
          }else{
            reject('a 1 error');
          }
        }, 3000)
      })

We can also directly create promises like this. Below I made another Promise:

      const a2 = new Promise((resolve, reject) => {
        setTimeout(() => {
            if(true) {
              resolve('a 2 Resolved');
            } else {
              reject('a 2 Error');
            }
        }, 3000)
      })

Then .then()I can make a callback call which will run soon after these two promises are completed. And the data from these promos will be arrayed in this callback function:

Promise.all([a1, a2]).then((promiseArr) => {console.log(promiseArr)}) 

The post Promise in JavaScript first appeared on Bipon's Diary.

Many of these young innovators working in Silicon Valley have established the world’s largest technology company. Many of them have married themselves and now become parents.

Some of them are now trying to get their own children to use these technologies and apps.

And they have no reservations about the ban.

Steve Jobs, the late Apple’s founder, once admitted in 20 that he and his wife, Lauren Powell, had set aside some time for their children to use these technologies at home.

Microsoft founder Bill Gates also tied his children’s time to the screen. Mobile phones were banned from reading tables.

Facebook founder Mark Zuckerberg wrote in a letter he wrote to his newborn August 29, asking him to “go out of the room and play”.

But why are Silicon Valley technology innovators trying to keep their children off the screen after becoming parents?

Technology-free childhood

Pierre Laurent, a tech company executive in the San Francisco Bay Area. He is also the board director of the Waldorf School of the Peninsular, a popular private school in Silicon Valley.

Students of this school avoided technology and apps until they reached adolescence.

Laurent, who sent his three children to the school to study, told the BBC that three-quarters of the parents there were somehow working at various tech companies.

They were asked by the school to keep an eye on the negative effects of these technologies on children’s education.

“When you were a kid, you had nothing to learn from a piece of glass. You have to actually use all the senses. You have to use the brain with everything you have,” he said.

Incompatibility

Waldorf School has been in the news ever since the news of the protests by Silicon Valley officials was published in the news.

Known throughout the world as a technology hub, the Silicon Valley school is emphasizing an education where children will benefit most.

The curriculum of this school emphasizes “the skills of the twenty-first century,” which includes the discipline of one’s life, the ability to think independently, work in groups, and to express everything artistically.

“These human capacities cannot be achieved by sitting in front of the screen. These qualities can be achieved only by doing different tasks in real life and by doing them manually,” said Pierre Laurent.

Like different

When one group of Silicon Valley parents think so, there is another team guardian who believes that this technology is an essential tool of education in the twenty-first century.

They think this technology is essential for doing well in the classroom as well as for success in outdoor life.

Marv Lapus, a senior director of Common Sense Media, a family that advises families on digital entertainment and technology, has been working for nearly a decade.

He says, “Yes, technology can waste attention, but how do we stand against it? Because there are many opportunities for children to use technology. They also have to be prepared for the real world. , “He said.

Finding the balance

The World Health Organization determined how much time children need to be screened. But recently they have reduced that time even more.

The company says it’s not okay to allow children under the age of two to see a screen with television alone. And for children two to four years old, the time limit is one hour or less.

But Lapus says not all screens should be considered in one row. He has two children. One is eight and the other is eight. He also talked about using their screens.

“It’s not okay to have as many screens as they used to do before. But the reality is I have to make dinner. But seeing Sesame Street is a great way to keep them entertained.”

Reference

The post Why people in Silicon Valley are against the use of technology for children first appeared on Bipon's Diary.

একজন মানুষ জীবনে কী করবে, সেটা অবশ্যই তার ব্যক্তিগত স্বাধীনতা। তাঁর নিজস্ব চিন্তা-চেতনা। কেউ যদি তবলা বাজাতে চায়, সে তবলা নিয়ে ঘুরবে। কেউ যদি চৌকিদার হতে চায়, তাহলে চৌকিদার হবে। তাতে কারো আপত্তি নেই। তবে কেউ যদি নিজেকে যাচাই না করে, নিজেকে পরখ না করে শুধু একমুখী ঝোঁকে, ঝাঁকের পালের সাথে দৌঁড়ায়—সেটা দুঃখজনক। ছেলে-মেয়েরা যখন নিজের ভিতরের সম্ভাবনাকে যাচাই করতে চায় না, তখন কষ্ট হয়। আমাদের দেশে যে বিসিএস-জ্বর এসেছে, সেখানে সম্ভাবনার খুন হতে আমি দেখেছি। বিসিএস দিয়ে চাকুরি করবে, তাতে দোষের কিছু নেই। দেশের সরকারী-বেসরকারী প্রতিটি কর্মকর্তা-কর্মচারীরই নিজস্ব গুরুত্ব ও অবদান আছে।

সমস্যা হলো, একজন তরুণ-তরুণী যখন মনে করছে তাঁর সামনে বিসিএস ছাড়া আর কিছু নেই—এটা নিজের জন্য ও সমাজের জন্য ক্ষতিকর। কেউ যখন ভাবছে, তাকে দিয়ে বিসিএস ছাড়া কিছু হবে না—সেটা আত্মঘাতী। বাইশ-তেইশ বছর বয়স, পৃথিবীর সবকিছু বুঝার বয়স নয়। সে বয়সের ছেলে-মেয়েগুলো যখন নিজেকে শুধু একটি গণ্ডির মধ্যে বেঁধে রাখে, তাতে সে নিজে বঞ্চিত হয়। সমাজকেও বঞ্চিত করে।

সমাজের সবাই একই কাজ করতে পারে না। একই বিষয়ে আগ্রহ নিয়ে দৌঁড়াতে পারে না। তাতে সমাজ ভেঙ্গে পড়ে। আঠারো থেকে ত্রিশ হলো গড়ার বয়স। নিজেকে শেইপ দেয়ার বয়স। চ্যালেঞ্জ নেয়ার বয়স। নিজেকে পরখ করার বয়স। নিজেকে দিয়ে কী হবে, কী হবে না—সেটা পরীক্ষা করার বয়স। যে ছেলে-মেয়েটি নিজেকে পরখ না করে, একজন বিসিএস কর্মকর্তা হয়ে রইলো—সে তো জানতেই পারলো না তাকে দিয়ে কী হতো, কী হতো না। একটা দেশের তরুণ-তরুণীদের রাষ্ট্রীয় চ্যালঞ্জ যেমন নিতে হয়, বৈশ্বিক বা গ্লোবাল চ্যালেঞ্জও নিতে হয়। তা না হলে সমাজটা পৃথিবীর মঞ্চে দাঁড়াবে কাদের নিয়ে?

বিশ্ববিদ্যালয়ের ফিজিক্সের একজন স্টুডেন্ট হয়তো হতে পারতো এস্ট্রনমির অধ্যাপক, কিংবা থিউরেটিক্যাল ফিজিসিস্ট। মেঘনাদ সাহা’র মতো ভাবতে ভাবতে একটি ইকোয়েশন দাঁড় করিয়ে ফেলবে। সে ইকোয়েশেনের সাথে তাঁর নাম জড়িয়ে থাকবে অনাগত কাল। কেমেস্ট্রির একজন শিক্ষার্থী হয়তো কাজ করতে পারতো প্রিন্সটন ইউনিভার্সিটির ফ্রিক রিসার্চ সেন্টারে। হয়তো উদ্ভাবন করতে পারতো নতুন কোন ম্যাটেরিয়ালস কিংবা ড্রাগ মলিকিউল। কৃষি বিশ্ববিদ্যালয়ের একজন শিক্ষার্থী হয়তো গবেষণা করতে করতে উদ্ভাবন করতে পারতো নতুন কোন ধান, সবজি কিংবা অন্যান্য শস্য। যে তরুণ ডাক্তার বিসিএস দিয়ে সার্জন হয়ে বসে আছে, সে হয়তো গবেষণা করতে পারতো স্ট্যানফোর্ড ইউনিভার্সিটির ব্যাকম্যান রিসার্চ সেন্টারে। সে কাজ করতে পারতো ফাইব্রোটিক ডিজিজ, এলজাইমার কিংবা অন্যান্য রোগ নিয়ে। কিন্তু এঁরাই যখন কায়মনোবাক্যে হাতে জপমালা নিয়ে সকাল-সন্ধ্যা বিসিএস জপতে থাকে, তখন খুবই করুণা হয়। কষ্ট বোধ করি।

কেউ যদি নিজেকে আবিষ্কারের চেষ্টা না করে নিজেকে সঁপে দেয়, তাহলে সে বহুজনকে বঞ্চিত করে। একটা বিশাল পৃথিবী থেকে নিজেকে বঞ্চিত করে। এটা দুঃখজনক। আমার জীবনে একটি বিসিএস পরীক্ষাই দেয়ার সুযোগ হয়েছিলো। সে পরীক্ষার লিখিত পর্ব দিয়ে আমাকে দেশ ছাড়তে হয়েছিলো। বিদেশে আসার পর ফল বের হলো। লিখিত পরীক্ষাতেও উত্তীর্ণ হয়েছিলাম। সে ফলাফল পেয়ে খুব দ্বিধান্বিত ছিলাম। পরে বুঝলাম, এই যে পৃথিবীকে দেখার এবং জানার সৌভাগ্য হয়েছে—নিজেকে যাচাই না করলে কোনদিনই উন্মোচন করতে পারতাম না। নিজেকে আবিষ্কার করেছিলাম নতুন পৃথিবীতে। যেখানে নিত্যদিনের সাথীরা হলেন, কালের সবচেয়ে আলোকিত মানুষ। এই গ্লোবাল প্রতিযোগিতায় নিজেকে জড়িয়ে বুঝেছি, এখানে যেমন চ্যালেঞ্জ আছে তেমনি আনন্দ এবং অর্জনের ব্যাপ্তিটাও অনেক বড়ো।

সঁপে দেয়ার আগে, নিজেকে পরীক্ষা করো, প্লিজ! তুমি যে যেতে পারো বহুদূর, সেটা তোমাকেই পরখ করতে হবে। ঝাঁকের সাথে দৌঁড়ে নিজের বৃহত্তর সম্ভাবনাটুকু খুন করো না।
……….
ফিলাডেলফিয়া, যুক্তরাষ্ট্র

Source

The post নিজেকে আবিষ্কার করো first appeared on Bipon's Diary.

#synchronous function

    function synch(func){
      func("synchronous")
    }
    synch(alert)
    alert('Test')

#Asynchronous function

setTimeout(alert,1000, "Asynchronous");
    alert('Test')

#Infinity Loop

function _1(){
      console.log('First function')
      _2();
    }
    function _2(){
      console.log('Second function');
      _1();
    }
    _1();

Now what’s the callback job? We know about the asynchronous behavior of JavaScript. If JavaScript takes time to do a task, do not wait and move on to the next code:

    const getCustomFunction = () => {
      setTimeout(function(){
        console.log('A function that takes some time');
      }, 3000)
    }
    const printAnotherFunction = () => {
      console.log('Another Function');
    }
    getCustomFunction();
    printAnotherFunction();

Running this code will show the next as before, and the next one for JavaScript asynchronous behavior:

From the definition of a callback function, we know that it is executed after another function is executed. And so we can use this technique here by writing two functions individually, but we can do it by the callback at the exact time the function is called:

    const getCustomFunction = (callback) => {
      setTimeout(function(){
        console.log('A function that takes some time');
        callback();
      }, 3000)
    }
    const printAnotherFunction = () => {
      console.log('Another Function');
    }
    getCustomFunction(printAnotherFunction);

We passed our function here as an argument inside our Main function call. And then I called it exactly where I needed it. This printAnotherFunction() function here is the callback function. It will give us results like mind. Means one after another. It will wait exactly 3 seconds then give the result. But serial maintenance does. Promise first, the data will come from it, then run the callback function:

The post Callback Function in JavaScript first appeared on Bipon's Diary.

Head

<head>

<link rel="stylesheet" href="smartphone.css"
media="only screen and (min-device-width : 320px)
and (max-device-width : 480px)">

<link rel="stylesheet" href="smartphone-landscape.css"
media="only screen and (min-width : 321px)">

<link rel="stylesheet" href="smartphone-portrait.css"
media="only screen and (max-width : 320px)">

<link rel="stylesheet" href="ipad.css"
media="only screen
and (min-device-width : 768px)
and (max-device-width : 1024px)">

<link rel="stylesheet" href="ipad-landscape.css"
media="only screen
and (min-device-width : 768px)
and (max-device-width : 1024px)
and (orientation : landscape)">

<link rel="stylesheet" href="ipad-portrait.css"
media="only screen
and (min-device-width : 768px)
and (max-device-width : 1024px)
and (orientation : portrait)">

<link rel="stylesheet" href="widescreen.css"
media="only screen and (min-width : 1824px)">

<link rel="stylesheet" href="iphone4.css"
media="only screen
and (-webkit-min-device-pixel-ratio : 1.5),
only screen and (min-device-pixel-ratio : 1.5)">

</head>

Reference

The post CSS3 Media Queries first appeared on Bipon's Diary.