First things first NodeJS is not a language but a mere runtime environment to allow JavaScript to be run on the Server. So the main question here would become why is JavaScript not preferred for cpu intensive tasks . As pointed out earlier that since JavaScript is a Dynamically typed language which allows for flexibility but at the cost of performance as the JSVMs have to at runtime and during execution figure out such things like type of variables unlike languages like C++ in which such things are caught during compile time. Regarding the question on why NodeJs environment is not preferred for cpu intensive tasks is that Node is designed to handle concurrent incoming connections and makes use of a concept called the Event Loop which is implemented through the C++ library libuv . The Event Loop orchestrates the different types of incoming requests and provides the results as and when they are available. The tricky part in Javascript Programming is not to write blocking code . What this means is that the execution of code should not be halted by a task which is not related. To give you an example consider the scenario that you have an API which just reads files from the fileSystem. Now suppose 2 users issue requests to read two different files of different sizes . There are two ways to handle this 1. Write Synchronous Code and Block the Event Loop this will result in the Event Loop to be blocked each time when reading from the fileSystem before it can address the other readfile requests although this will be some milliseconds but i hope you are getting the bigger picture. The second way to handle this is write Asynchronous Code and Not Block the Event Loop , this will keep the event loop running and what this will do is schedule these Asynchronous calls in a stack and once these calls are over they pass control back to the Event Loop to handle the output request from these calls. And there are many ways you can do cpu intensive tasks in NodeJs. One being that you can fork new processes to handle really CPU intensive and recently Nodejs has come up with the worker threads concept which might also be useful in this case. Hope i answered what you were looking for ... Please let me know if i was not clear on anything in my answer

I find syntax related questions really dumb. I think as developers we should focus on how a person approaches a problem rather than if he has good syntactical knowledge of one language. I may be pointing towards a more algorithmic approach but i too hate questions like the one pointed out by Ehsan Fazeli . And yes the also the How you rate yourself question . The GitHub approach is nice but even if a person is not very much active on Github we can still get a better idea of a persons grasp on particular concepts without asking them trivial questions.

I have no experience in Native app development but i would like to point out that instead of building a native app you can also use the same app to be deployed for a mobile or tablet by converting the app to a Progressive Web App. In this you would have to create a service worker which will be installed on the target device, which is much like a bookmark but will be along with an Icon and would feel like an app. So it is essentially the web app being served to the user making it feel like a native Andriod app. You can read more about them in the below mentioned links. https://developers.google.com/web/progressive-web-apps/ https://developers.google.com/web/fundamentals/codelabs/your-first-pwapp/ Also to get a feel of what i am saying try and visit trivago website on your phone, then it will ask you to install on your phone. This is will install the service worker on your phone and then you can use trivago just as you would if it would be an app.

Firstly i would like to say that unlike windows if a file is deleted in Linux it cannot be retrieved. I can see that you have used mv "$file" "${file/*.jpg/$$$.jpg}" , $$ in Linux refers to the PID of the process and in your case it would refer to the PID of the bash process which will be the same in each case. Therefore a single file with the name PID$.jpg will be created i.e if your bash PID is 1234 the the file created will be 1234$.jpg and with each iteration the same file will be re-written. I hope this makes sense. If you wanted to write a script which would rename each file concatenated with the bash process id the below might be helpful. But test it once before you use it in production. for file in *.jpg do mv " $file " ` echo $file | awk -F "." '{print $1}' `.$$.jpg done

As said before that this is not a recurrsive problem but just how hoisting works with JS. The code posted you would be executed in the following manner. ( function f ( ) { function f ( ) { return 1 ; } function f ( ) { return 2 ; } return f(); })(); So when the execution reaches the return statement the definition of the function is the second one and hence your return statement is 2 and 1 will never be returned.

Stop propagation prevents the event to bubble upwards to the parent. Consider the following HTML example. < div id = "parent" > Parent div < p id = "para1" > Paragraph element in the div </ p > < p id = "para2" > Another paragraph element </ p > </ div > < a id = "link" href = "www.google.com" > Click me </ a > Now we will define the behavior of the above elements using Javascript. I will use jquery for a simplified code. $( "document" ).ready( function ( ) { $( "#parent" ).click( function ( e ) { alert( "Parent Clicked" ) }) $( "#para1" ).click( function ( e ) { alert( "Paragraph 1 clicked" ) }) $( "#para2" ).click( function ( e ) { e.stopPropagation(); alert( "Paragraph 2 clicked" ) }) $( "#link" ).click( function ( event ) { event.preventDefault(); }); }) In the above example as you can see that we have 2 child paragraph components of a parent div component. And to each component we have attached a click event. So when we are clicking a paragraph element(child) we are also clicking the div element(parent). So in the above example when you click on paragraph 1 you get an alert "Paragraph 1 clicked" and then you get an alert "Parent Clicked". But when you click on paragraph 2 you only get the alert "Paragraph 2 clicked" and the event is stopped there and does not bubble to the parent div element. For event.preventDefault(); in the above example there is a link which points towards google.com. But instead of navigating to google.com you can put some other behavior like an alert or something.