I am reading Reactjs documentation and came across mixins,but i dont understand mixins clearly.What are mixins and what are they used for?
In "", Mark Lutz mentions "mixins". I'm from a C/C++/C# background and I have not heard the term before. What is a mixin?   Reading between the lines of  (which I've linked to because it's quite long), I'm presuming it's a case of using multiple inheritance to extend a class as opposed to 'proper' subclassing. Is this right?   Why would I want to do that rather than put the new functionality into a subclass? For that matter, why would a mixin/multiple inheritance approach be better than using composition?  What separates a mixin from multiple inheritance? Is it just a matter of semantics?
Do I need a visa for Georgia? I am a Nigerian, holding a valid schengen visa issued by the French embassy, and a multiple entry visa for the United States. Will I be allowed to enter Tbilisi in Georgia? How can one have a mini table of contents for the current chapter appear just after the chapter name listing all sections of that chapter? Python Flask shutdown event handler Taylor's Remainder $x-\frac{x^2}{2}+\frac{x^3}{3(1+x)}<\log(1+x) <x-\frac{x^2}{2}+\frac{x^3}{3}$ Prove that   $\displaystyle x-\frac{x^2}{2}+\frac{x^3}{3(1+x)}&lt;\log(1+x) &lt;x-\frac{x^2}{2}+\frac{x^3}{3}$  My attempt: I can prove this by taking one side at a time and assuming $\displaystyle f(x) = \log (1+x)-x+\frac{x^2}{2}-\frac{x^3}{3}$   and then proving that it is a decreasing function and then the same for the other side.  But I am looking for a better solution using Lagrange's Mean Value Theorem or using Taylor's remainder. How to get current CPU and RAM usage in Python? Where can you find the quantities of each amino acid of a particular protein or food? Use of Indefinite Articles(a,an) Consider the following sentences:  I am staying in a hotel nearby. I am staying in an hotel nearby.  I know that both are correct. But I would like to know why? I do not see any proper reason for the second one as the 'h' is not silent as in French. So, what could be the reason? Implications and Ordinary language Possible Beamer bug: Frame number has different color than date in infolines footer I use TeX Live on Mac and I get my weekly updates through the TeX Live Utility. I am working on some slides for an upcoming talk. I am using the same Beamer templates and settings that I always use, so I was surprised to see that the page numbers that I always include at the bottom of my slides suddenly appeared in a different color. Here's an MWE:  \documentclass{beamer} \useoutertheme{infolines} \usecolortheme{beaver} \title{Title} \date{\today} %\setbeamercolor{page number in head/foot}{fg=darkred!60!black} \begin{document} \begin{frame} \end{frame} \end{document}     As you can see in the bottom right corner of the slide the page number appears but its color looks off. Until recently it would look exactly the same color as the date appearing next to it.  By Googling around a bit I managed to figure out how to get this to look normal again using the line commented out in the code above:  \setbeamercolor{page number in head/foot}{fg=darkred!60!black}   By uncommenting this line I got back the desired behavior:    So my question is not so much about how to fix this problem, but about why this is happening in the first place. Is this a bug that was introduced in a recent update, and if so will it be fixed? Is this a deliberate choice on the part of the developers (if so I can't imagine why)? Or am I doing something wrong or is something broken in my TeX setup?  I'd appreciate any insight on this. Thanks in advance! How do file permissions work? How can I make sure that my on-screen colors are consistent? How to show the full path of a file or directory in the terminal? I need to know how the directory name in order to type it out in the terminal. How do I access the names of directories?   Windows Explorer used to have a title bar with the full path. Can someone please help me figure out how to see the full path of a certain file? How to find the running network services and the port and user I want to find a list of all network services running on my system, including details of the port and services and the users. I know that I need to use netstat, ps and fuser. but I don't know how to write the command. Do I need to write a shell script to find all of them? or I can use in a line of commands? Thanks for your help. I believe that Asimov himself recommended reading them in chronological order, however I read them in the order that they were published and think that this is the best way to do it.  What is the correct order? Each package name is in the form: package-XubuntuY*_amd64(i386)  So my questions are:   What does the X stand for? What does the Y stand for?   for example binutils_2.22-6ubuntu1.3_amd64  What is the meaning of the numbers 6 and 1.3 Can I fine-tune my screen brightness? My laptop is Lenovo T400, and my OS is Ubuntu 10.10. I change the brightness of my screen by pressing the FN key and one of the two keys for increasing/decreasing brightness.  The brightness I feel comfortable is between two consecutive levels that are offered. So I wonder if it is possible to fine-tune the screen's brightness? Question on showing a bijection between $\pi_1(X,x_0)$ and $[S^1, X]$ when X is path connected. I am trying to do this question taken from Hatchers algebraic topology and I am struggling to understand the notation and the concepts.  As far as I know $\pi_1(X,x_0)$ is the set of end point preserving homotopy classes of loops in X based at $x_0$ and a loop is just a path    $f:I \rightarrow X$ with $f(0)=f(1)$. The question says we can regard $\pi_1(X, x_0)$ as the set of basepoint preserving homotopy classes of maps $(S^1, s_0) \rightarrow (X, x_0)$.   This confuses me, does it mean the set of basepoint preserving homotopy class on maps $g:S^1 \rightarrow X$ which map loops in $S^1$ based at $s_0$ to loops in X based at $x_0$?  Then how can $\pi_1(X,x_0)$ be regarded as this set?  If someone could explain this it would be really useful "ping: unknown host google.com" but IPs works fine How to convert Wubi install into regular install? What part of speech is “there” when used in “There is (blah blah)”? What part of speech is there in the sentence “There is a book on the table?”  Also, while typing it out, another question pops up vis-à-vis punctuation. In my complete first sentence above, I ended it with a question mark since my main sentence is a question. The quote is not a question, but it looks like it because of the question mark. Is this the right way to punctuate?