Sunday, February 14, 2016

JavaScript will evolve faster as a language than a compile target

Author:Kamanashis Roy
Note: I wrote this blog on request

JavaScript survived and thrived to be one of the most popular language for web development. There was concern over the best-practice and performance issue in JavaScript. Some people went further to say JavaScript language is Buggy. But it served it’s purpose as client-side scripting.

The main criticisms against JavaScript were,
- JavaScript has fragmented implementation( because of the lack of standardization and the browser-war.)
- Standardization that resulted JavaScript to be compiler target rather than a language itself.
- JavaScript is slow.

The criticism against the JavaScript gave rise to compilers that target it. These source-to-source compilers generate acceptable JavaScript code. One of them being Google Web Toolkit. It generates JavaScript from Java. The idea is to impose the best practices. Again after standardization and wide-spread acceptance of JavaScript there have been development in source-to-source compilers that target JavaScript. But JavaScript eventually is more popular for web-development than those compiled language. Let’s see how JavaScript got away with the criticisms.

Fragmented implementation and lack of standardization

The browser-war gave rise to reversed-engineered implementations of JavaScript. And individual programmers could not effort time to write JavaScript for each browser. So some people preferred to generate automated code for different browsers using compilers.

To solve the problem Netscape allowed it to be standardized as ECMAScript. Now there are multiple open-source implementations of JavaScript. And the most popular of them uses Just-in-time compilation. So it provides better opportunity to write uniform code for the developers. Again there are frameworks like jquery that wrap the platform depended code to give an uniform API. Finally the fragmentation is not a problem anymore.

Standardization that resulted javaScript to be compiler target

Again the cross-browser compatibility of javaScript gave the rise of source-to-source compilers (such as Emscripten) that target asm.js and NaCl. The asm.js is precompiled(ahead-of-time compilation) javaScript that allow the browser to run asm.js based application much faster.

JavaScript is slow

JavaScript performance is affected for varied reason. One of them being the support for dynamic type. Another being the dynamic binding. There are ways to get away with this things. The V8 engine actually uses JIT compiler that compiles the javaScript into native code on runtime, instead of interpreting. And the V8 developers compare the JavaScript performance with C/C++. They have some best practice suggestions about JavaScript. The idea boil down to ,

  • not to use undefined rather use static types,
  • to avoid arrays of varying types,
  • finally to use less constructors and initialize all the variables in the constructors.

The poor coding can be identified by some static analysis. And these tools can be integrated in the IDE and browser. This way the programmers get notified of the performance issues.

Frameworks are the right way

Now there are some emerging trends of development regarding JavaScript. It is done by some frameworks and runtimes. Some of them are,

  • jquery(It is more like library than a framework with easy-to-use API with a lot of open-source modules),
  • prototypejs,
  • threeJS,
  • reactJS,
  • backboneJS
  • nodeJS(Not a framework but a runtime for server-side-javascript and desktop application, it features a lot of packages/modules as npm),

Some of them are domain specific and some are for general use. These frameworks feature popular programming patterns for object based language. They allow us to use those well-written patterns. It makes the user code small. It is like “write less do more”. Less code gives less bugs and may be less performance hazards. In that sense less is good. Again these frameworks allow us to write browser independent code. These frameworks also take advantage of the ahead of time compilation. This is why they are immensely popular.

A note on nodeJS

NodeJS is the JavaScript runtime that works on the vast range of platforms. It uses event-driven approach of concurrent programming which is closely relates to observer-pattern that is popular in Object-Oriented paradigm. There were a lot of issue dealing the concurrency and scalalibity in server-side scripting. NodeJS was keen to solve the problem in event-driven way. And as JavaScript is already popular in the web-development arena, NodeJS got huge success. It is supported by big companies. And there is an package-ecosystem, npm, based on nodeJS.

Again there are a lot of frameworks that work on top of NodeJS. Some of them being Express.js, and Koa.js. And there is popular Atom IDE(runs over ioJS/(nodeJS variant) runtime) that support development based on NodeJS and JavasCript.


As a C developer, I want to share that I like C so much. But I also knew that it contains a lot of blotted code. It makes things harder because it does not have a memory manager. But one intriguing thing about C is the portability as the ability to compile it in wide range of platforms, in the same way JavaScript has portability in the browser.

I worked on those things and I wrote a compiler that eventually generates C code out of Object-Oriented garbage collected code. And I grew some framework to support server-side development. I targeted C the same way that the source-to-source compilers target JavaScript.

But sometimes I get back to C for some reason. I discovered that my framework written in C also support doing cool things with small dependable code. I think my compiled-framework gave me greater understanding of cool stuff in C.

I think the compilers targeting the JavaScript are also giving new directions for JavaScript based development. JavaScript is now getting developer attractions by featuring runtimes, frameworks and IDEs. In fact there are a lot of packages available on these frameworks. Now they are also being used as desktop tools(GUI), command-line application and server-side scripting.

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