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The Latest JavaScript Topics

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CoffeeScript: a TDD example
CoffeeScript is a language building an abstraction over JavaScript (as the similar name suggests.) It is an abstraction over the syntax of JavaScript, not over its concepts: the language is still based on functions as objects which may bind to other objects, and prototypical inheritance. CoffeeScript favors the best practices of JavaScript by transforming abstractions you would have written anyway, or borrowed from a framework, into language concepts for maximum conciseness. It has a compilation step - as every language must compile to a lower-level one, like C or Java. Since cowboy coding is not my preferred way to work, I prepared a Test-Driven Development example by using jsTestDriver. In this article, you get two things: a CoffeeScript introduction, and the tools for unit testing it (and consequently, how to TDD with CoffeeScript). Building on Top of JavaScript There is something to be said for those who go out of their way to try to improve the infrastructure of existing programs. Many have taken a stab at it by creating tools that are a compliment to JavaScript, and it appears to have worked quite well in this case. The reason? Because JavaScript is in need of some improvements. One of the programs that people have come up with is CoffeeScript. It is literally a bit of computer code that overlays the existing JavaScript codes to make it read even more fluidly. The benefit that one gets from this is that they can start to use JavaScript in a more efficient way with fewer bumps in the road. As it stands right now, JavaScript has numerous challenging issues that we must recognize. However, that can all be amended by using JavaScript as it was intended and just working towards perfecting it. CoffeeScript is certainly not the end all be all of the programs for improving JavaScript, but it is a great step in the right direction. People should at least try out the CoffeeScript code to see if it may be useful to them in terms of improving the quality of codes that they receive from JavaScript. If so, then it will have been worth the trouble. The infrastructure The basic structure consists of two folders: src/ and lib/; remember the compilation step. We'll put .coffee files into src/ and compile them to .js equivalents in a symmetrical tree in lib/. We add also a jsTestDriver.conf file to tell the unit testing framework all the files to load, which are only the "binary" .js scripts: server: http://localhost:4224 load: - lib/*.js Compiling This is the first version of the test I've managed to write, fizzbuzztest.coffee. It is a tautology that should always pass: mytest = () -> assertEquals(1, 1) tests = { "test1is1": mytest } TestCase("tests for fizzbuzz kata", tests) You see here that functions are still first-class objects, but only anonymous functions are supported. CoffeeScript is a Python/Ruby-like language without semicolons, and there are some affinities and common backgrounds with the latter language. I still use the old syntax for calling functions for now, although parentheses can be omitted in many cases. CoffeeScript is conservative, and even accepts semicolons if you want to write them. I compiled this script with coffee -o lib/ -c src/. fizzbuzztest.js is the result: (function(){ var mytest, tests; mytest = function() { return assertEquals(1, 1); }; tests = { "test1is1": mytest }; TestCase("tests for fizzbuzz kata", tests); })(); The global namespace is not touched by default, and var keywords are automatically introduced to preserve it. When I later needed the global namespace, I wrote: this.fizzbuzz = /* ... function definition ... */ This in this case is the window object or the other global object where you execute the code. Running To run the test, we must initialize the test driver (only once): jsTestDriver java -jar JsTestDriver-1.3.2.jar --port 4224 jsTestDriver will now listen at localhost:4224. Load this URL in your browser and capture it by clicking on the link. Tests will be executed inside the browser when requested: for more details see the related article. Every time you want to run the tests, execute them from the command line: java -jar JsTestDriver-1.3.2.jar --tests all This is the complete history of my kata. Here is the final version of the code (spoiler alert!), with support for addition of other factors than 3 or 5. The code is probably uglier than average, but it compiles: tests = { "test ordinary numbers are unchanged": -> assertEquals(1, fizzbuzz(1)) assertEquals(2, fizzbuzz(2)) assertEquals(4, fizzbuzz(4)) assertEquals(142, fizzbuzz(142)) "test multiples of 3 become fizz": -> assertEquals("Fizz", fizzbuzz(3)) assertEquals("Fizz", fizzbuzz(6)) assertEquals("Fizz", fizzbuzz(9)) "test multiples of 5 become buzz": -> assertEquals("Buzz", fizzbuzz(5)) assertEquals("Buzz", fizzbuzz(10)) "test multiples of 3 and 5 become fizzbuzz": -> assertEquals("FizzBuzz", fizzbuzz(15)) assertEquals("FizzBuzz", fizzbuzz(45)) } TestCase("tests for fizzbuzz kata", tests) newRule = (word, divisor) -> (number) -> return word if number % divisor == 0 "" newFizzBuzz = (rules) -> (number) -> result = "" concatenation = (rule) -> result = result + rule(number) concatenation rule for rule in rules return result if result number fizzRule = newRule("Fizz", 3) buzzRule = newRule("Buzz", 5) this.fizzbuzz = newFizzBuzz([fizzRule, buzzRule]) Comments On The Experience CoffeeScript offers a shorter syntax, which presents a bit of a learning curve but not a steep one. I went through the whole example in 1 hour (I already knew how to use jsTestDriver, however.) Syntax shapes how you write code by making some things easier: I found myself using higher-order functions which create other ones more often, since creating a function now is just a matter of putting -> before some lines of code. Variable naming is also simpler as you just have to think of the name, not about var or polluting the scope. More time to dedicate to design, and less to language issues. Some one-liners like the instruction if the expression is handy but not essential, and are there due to Ruby's inspiration. There's, even more, to discover in CoffeeScript, such as the options for the binding of functions which helps not to lose the reference to this. However, the question is if all this convenience has more value than the time spent to learn a new language and add infrastructure to make it work - the compiler, the build hooks, and the parallel tree to ignore in your version control system.
August 12, 2022
by Giorgio Sironi
· 15,756 Views · 1 Like
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Rust’s Ownership and Borrowing Enforce Memory Safety
By using an ownership model, Rust takes a novel approach to ensure memory safety at compile time.
August 11, 2022
by Senthil Nayagan
· 5,508 Views · 2 Likes
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Problems With Kafka Streams: The Saga Continues
Problems with the old version of Kafka haven't been solved completely. Some shortcomings have been fixed while some problems have been introduced. The cycle continues.
Updated August 10, 2022
by Aleksandar Pejakovic
· 17,704 Views · 11 Likes
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Introduction: Querydsl vs. JPA Criteria
This article presents an introduction to the Querydsl series with the goal to highlight the difference from JPA Criteria.
Updated August 9, 2022
by Arnošt Havelka DZone Core CORE
· 19,926 Views · 8 Likes
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Build a Java Microservice With AuraDB Free
For today’s adventure, we want to build a Java microservice that connects to, and interacts with, graph data in a Neo4j AuraDB Free database.
Updated August 8, 2022
by Jennifer Reif DZone Core CORE
· 10,011 Views · 5 Likes
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Event Loop in JavaScript
JavaScript is single-threaded, meaning only one action can be performed at a time. Event Loop is the queue of commands to be called.
August 8, 2022
by Sebastian Z.
· 6,234 Views · 2 Likes
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ExpectedConditions in Selenium
In this Selenium tutorial, you will learn how to use Expected Conditions in Selenium to fix timing-related issues due to the dynamic loading of WebElements.
August 6, 2022
by Himanshu Sheth DZone Core CORE
· 12,376 Views · 3 Likes
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Diving Deep into Smart Contracts
Smart contracts allow two parties to enter into an agreement. Take a deep dive into smart contracts to see how to reuse a single contract over and over again.
August 5, 2022
by John Vester DZone Core CORE
· 76,777 Views · 5 Likes
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Onboarding New Users With Coinbase Wallet
Learn how to make onboarding new users to your Web3 DApps easier by using Coinbase Wallet, then see how it's done with the included project and code samples.
August 4, 2022
by Michael Bogan DZone Core CORE
· 6,062 Views · 2 Likes
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CockroachDB and Deno: Combining Two “Quick to Start” Technologies
This tutorial connects Deno with CockroachDB. Explore Deno CLI, Deno Deploy, CockroachDB, CockroachDB Serverless, and beginner TypeScript and SQL concepts.
August 2, 2022
by Morgan Winslow
· 4,827 Views · 1 Like
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How to Leverage Speech-to-Text With Node.js
Speech recognition has a variety of important uses in consumer and commercial technology alike. Take advantage of a free speech-to-text API with Node.js code examples.
July 29, 2022
by Brian O'Neill DZone Core CORE
· 9,216 Views · 2 Likes
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Selenium vs Cypress: Does Cypress Replace Selenium?
Learn how Cypress compares to Selenium, a better choice in the software testing world, in terms of speed test, architecture, language support, and much more.
July 28, 2022
by Shormistha Chatterjee DZone Core CORE
· 18,223 Views · 3 Likes
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Combining gRPC With Guice
In this article, see what scopes are provided by grpc-scopes lib and when and how to use them.
July 28, 2022
by Morgwai Kotarbinski
· 8,001 Views · 4 Likes
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Migrating From Sakila-MySQL to Couchbase, Part 5: JavaScript User-Defined Functions
Explore this comparison with Sakila DB-MySQL user-defined functions and stored procedures using the new JavaScript functions on Couchbase.
July 27, 2022
by Isha Kandaswamy
· 5,418 Views · 1 Like
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Use of JavaScript In Online Games
While HTML5 and C++ might be the first languages that you think of when you think of games, JavaScript has a big role in game development, too.
Updated July 27, 2022
by Julia Beyers
· 15,766 Views · 7 Likes
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Top 10 Benefits of ReactJS for Your Application Development
Having plenty of feature-rich components, tools, and libraries, front-end development has been one of the most exciting and multi-faceted tools.
July 26, 2022
by Kiran Beladiya
· 5,676 Views · 1 Like
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A Brief History of JavaScript
JavaScript is one of the most important languages today. Let's take a look at how JavaScript has evolved in its short history and where it is headed next.
Updated July 25, 2022
by Sebastián Peyrott
· 12,968 Views · 13 Likes
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50 Common Java Errors and How to Avoid Them
Bogged down with Java errors? This series presents the 50 most common compiler errors and runtime exceptions that Java devs face, and how to conquer them.
Updated July 25, 2022
by Angela Stringfellow
· 148,775 Views · 30 Likes
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CSS3 Transitions vs. jQuery Animate: Performance
Animation Brings a Whole New World to Life Where would we be without animators helping us see the world in a whole new light? It seems that we easily forget the hard work that these people do, and that is truly a tragedy. There are so many people helping us see the world for the way that it truly is, and we should be thankful and respectful of the hard work that they are doing. That is why we also have to ask ourselves if we should be using CSS3 Transitions or jQuery Animate when looking for the right program to do our animation work in. You might think that animation is just something used to create children's movies and television shows, but that isn’t quite right. It has a wide range of uses in our world today (more on this later), and we are increasingly coming to rely on it to make critical decisions about how we move forward on some of the most important decisions that we have to make to keep our world moving forward the way that we want it to. Take some time to step back and recognize all that animation has brought us, and this will help you better understand why there are a lot of people who are pushing to figure out which software programs can bring them the best animation outcomes. Rich Bradshaw has written a detailed tutorial series on CSS Transitions, Transforms, and Animation. That alone is worth reading; but in case you weren't convinced, Rich also put together a little (and maybe a little unfair) performance comparison: A head to head comparison of CSS transitions and jQuery's animate. Rather than setting a timer to run repeatedly, transitions are handled natively by the browser. In my rather unscientific testing, transitions are always quicker, running with a higher frame rate, especially with high numbers of elements. They also have the advantage that colours can be animated easily, rather than having to rely on plugins. Putting it All to the Test The best way to compare the two programs against one another is to put them through a series of simulated tests that allow each program to prove what it has going for it. Believe it or not, that is exactly what some people have done. They work with the two programs to see how they adapt and react when put under various testing conditions. By doing exactly that, the programs must prove themselves in the sense that they are forced to show that they can keep up with rapid changes and shifts in the dynamics of the work thrown at them. These tests can all be sped up by using computer simulations to run the tests instead of putting actual work done by a human being through the testing period. You will find that there is a lot to be gained by going through all of this and figuring out just how much each system can potentially get through. You don't want to use something that is sub-par compared to the other programs on offer out there, and that is why we are all so grateful that there are people who are willing to work with both programs to test them and see what the ultimate outcome really is for each. Unsurprising Results You should not be shocked to learn that CSS3 Transitions is the better program to use. It has a more seamless transition from image to image, and the speed with which it can process all of that data is truly amazing as well. The fact that there are multiple programs available for us to choose from is a great thing, but there is really no competition between CSS3 Transitions and jQuery Animate. The CSS3 Transitions program has been around for a lot longer, and it has the ability to get results from its users much more easily. The results probably won't surprise you, and the conclusion is inevitable ('use CSS3 for animation when you can') but Rich's analysis (scroll down), using the Timeline view in the Webkit Inspector, is pretty neat: (Actually, the Timeline is pretty neat, period. I didn't know about it until now..sweet.) So check out Rich's test and performance discussion, and maybe use Webkit Inspector's Timeline for performance fine-tuning in the future. Animation Into the Future The tools that are used in the world of animation are going to continue to be called upon to help creators do the challenging work that they do. The demand for animated films and television series has not ceased, but the usefulness of animation goes far beyond being entertained. There are uses for animation in simulations of all kinds. Even the military uses animation to simulate certain battlefield conditions and other concerns that they know are relevant to their operations. It is something that has helped them sort out how they can best move forward with their plan of action whenever the need arises. Put another way, the military uses animation to make sure they are never caught off guard. Courtrooms are seeing an increasing amount of animation used in presentations put on both by prosecutors and defense counsel alike. They make reenactments of various aspects of an alleged crime using animation to help a jury see how they claim that things happened from their point of view. There are a lot of reasons why this helps juries to understand their point of view more completely. CSS3 technology is helping to make the use of animation more widespread and available to a larger number of people across all walks of life. It appears likely that this trend will continue, and there are many people who are counting on using CSS3 technology for several projects that they have in the works at this time. We should all celebrate the fact that such technology is making animation more accessible. Using the Best Programs Doesn’t Have to Be Costly One more thing to keep in mind when you look for the best programs for animation purposes is this: They don’t have to be costly. Many programs are free and/or open-source. Even the ones that you have to pay for aren’t necessarily wildly expensive. They provide a huge ROI when you put them to use, and that alone should get you to understand why they are so important to use. Make sure you consider this and consider the options that are before you when it comes to selecting an animation program that will do the work you need it to do. The last thing in the world that you want to have to happen is to produce lower-quality animation just because you insisted on trying to save a few dollars by going with a less expensive animation program.
July 24, 2022
by John Esposito
· 24,454 Views · 1 Like
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Building an HTTP Tunnel With WebSocket and Node.JS
Introduce about how I build a HTTP tunnel tool based on WebSocket.
July 23, 2022
by Embbnux Ji
· 4,356 Views · 1 Like
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