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Javascript String: ECMAScript standards

This is the second article highlighting some of the latest improvement issued in the most recent released of the ECMAscript for javascript string.

The first article covered classes and is named:  Javascript Class: ECMAScript standards.

Javascript String

String is one of the most primitive object and most used in any programming language. It the most recent ECMAscript releases (starting from the 2015), javascript string have received some updated and improvement that will support developers in their usage.

This article will cover changes like templates literals, replacements, concatenation and tagged templates literals by offering brief descriptions and code snippets where appropriate.

Template literals

Template literals also known as “template strings”, can be accessed by the use of the back-tick (`) characters, differently from the basic strings that are initialised with single or double quotes.

This are very powerful as they enable string manipulation without the overhead that that we have had to use until now. The first feature of template literals that we are going to cover is the ability to specify multi-line strings.

Multi-line String

Javascript multi-line string have until recent being defined by ending the string with “/n” and a “+” sign, Like the example below.

old multi-line
 
console.log('This is my first line 1\n' +
'and this is my second');

This code, even if probably quite easy to write, it is not easy to maintain and not nice to read (breaking one of the rule of clear code).

If declaring a string with template literals notation, you will actually be able to define multi line string without the need of any additional character. The example below will actually output the same as the one previously shown.

Template literals multi-string
 
  1. console.log(`This is my first line 1
  2. and this is my second`);

String replacement “embedding”

String embedding or replacement occurs when we try to dynamically create a string by adding an expression or a variable within it. This is personally one of the feature that I really hate in Javascript. Most of the common languages had string manipulations methods and finally, this feature are also available to the Javascript developers.

Prior to the template literals you may have use the following to create a dynamic javascript string.

expression interpolation
 
var a = "Fifteen";
var b = 5;
console.log(a + 'is ' + (b * 3) + ' and\nnot ' + (b * 2) + '.');
// "Fifteen is 15 and
// not 10."

The above is not only quite tricky to write as it require lots of parenthesis and quotes, but it is also very hard to read compared to the following, that as with all the other examples, will output perfectly the same.

template literals: expression interpolation
 
var a = 'Fifteen';
var b = 5;
console.log(`${a} is ${b *3} and
not ${b * 2}.`);
// "Fifteen is 15 and
// not 10."

 Tagged template literals

This is an advanced for of template literals. It will enable you to create a function that can be used to parse you template literals.

The return value of this function does not have to be a string, but in the following example we show the “basic” feature.

tagged template literals
 
function tagExample(strings, valueOne, valueTwo){
    //the strings is the array of strings, each item separated by one of the value
    let firstPart = strings[0];
    let secondPart = strings[1];
    let thirdPart = "";
    if(valueOne >= valueTwo){
        thirdPart = "therefore younger than me."
    }else{
        thirdPart = "therefore older than me."
    }
    return `${firstPart} ${valueOne}
    ${secondPart} ${valueTwo}
    ${thirdPart}`;
}
tagExample`I am ${myAge}while my brother is ${myBrotherAge}`
//OUTPUT
"I am  15
while my brother is  30
therefore older than me."

String prototype methods

The following paragraphs are going to cover useful methods that have been released since the ECMAscript 2015.

javascript string includes

This new method is surely going to put a smile on your face. As a developer, I have used the following OLD method many times, and every time I had to go through over at least twice to make sure that it was returning the correct behaviour.

The include method will allow you to search for a specific string and will return the position. This was previously done using the indexOf() method like the example below.

indexOf
 
var stringToSearch = "This is a very long string";
stringToSearch.indexOf("string") !== -1;
//true

We are now able to easily obtain the same result using the includes() method. This method also allows us to pass a second paramether that specifies where the string starts.

string.includes()
 
var stringToSearch = "This is a very long string";
stringToSearch.includes("string");
//true

javascript string repeat

The name of this method is self explanatory. It allows you to repeat a specific string for a X number of times

string.repeat
 
let var1 = "etc ";
var1.repeat(3);
//etc etc etc

javascript string startsWith and endsWith

This helpers return a Boolean value and also support a second parameter that is the position to where the string check starts.

string.startWith
 
var string1 = "Start with a simple word and finish with another.";
string1.startsWith("simple ", 13);
//true
string1.endsWith("Start");
//false

Browser support

At time of writing, the features covered in this article are largely supported in all the main used browsers ( includes mobiles browsers), with the only exception of IE11 and is still not supporting this features as showed by the graph below or as it can be found in by following this link to caniuse.com website.

teamplate literals
teamplate literals

Conclusion

Even if the above feature may not be the most exiting introduced by the ECMAscript standards, they are surely going to make your day to day life a lot easier. Productivity can surely increase and this small methods will not only make you develop faster, but will also make your code more readable that is what most of us hope to achieve.

Phaser Game Part 1: Set up Node Js Server and PhaserJs

This post is part of a series of blog posts aimed to describe the step by step process of creating an browser game with PhaserJs using the latest ECMAscript standards.

This post in particular will set up the basic requirement for the game (server and file structure).

The Tech stack

For this game, I am going to use NodeJs and Express as our back-end server.  I usually use side project like this to gain experience on new territory, but this does not indicate that other servers may be less suitable.

Most of the game and all the game engine, are handled by the browser ( hence the name browser game) and therefore the Server does not play a key part and using nodeJs may actually be a good lightweight option.

The Javascript will be written using the latest ECMAscript 6 standards (please check current support from other blog post). This will enable us to investigate and lean the new standards, while developing the game. (Achieving two objects at once).

Set up the Work Station

Folder Structure

Game

->Server.js

->Index.html

->Assets //This will include all the images and sprites

->Js //This will include all the js file required for our game

->External //This will include the phaser.js library

NodeJs

To install node js you need to download the latest stable version from the Node.js download page. The installation process is quite simple and quick.

After installing node, we will then be able to install all necessary packages by using the NPM software registry, directly from the command prompt.

Express

The first requirement for our small server, will actually require us to install an NPM package called express. This package is one of the most comprehensive web application framework available for NodeJs. To install it you will need to enter the following in your command prompt window:

Install Express
 
cd c:/game/
npm install express

If you are not familiar with the command prompt, in the above snip of code we have firstly navigated to a specific folder, then run the “npm install” command specifiying the name of the package we wanted to install “express”.

This is all that is needed to install new packages using the NPM (Node Package Manager).

Code Editor

There is no requirement for  a code editor. PhaserJs can be ever be developer in a basic notepad.

For personal experience I would suggest one of the following:

  • Visual Studio Code
  • Atom
  • Sublime
  • Nodepad++

Basic Server

To create a web server using Node and Express we just need a couple of lines of code. More information can be found on the express website.

The following code need to be inserted in the file names Server.js.

Basic express server
 
//Example usage in the command prompt
//node Server.js
// Parameters
const port = 880; //Specify a port for our web server
const express = require('express'); //load express with the use of requireJs
var app = express(); //Create an instance of the express library
app.use(express.static(__dirname + '/'));//Serving static files
app.listen(port, function() { //Listener for specified port
    console.log("Server running at: http://localhost:" + port)
});

The code is heavily documented for illustration purpose. Please also note the use of the “const” type.

To run our server we just need to enter the following in our command prompt

run express server
 
node Server.js

Web page

Now that our server is now ready, it is time to create our first webpage.

To do so, just enter the following in the Index.html file:

Basic Index page
 
<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8" />
    <title>My Game with PhaserJs</title>
</head>
<body>
    <h1>Welcome to my game</h1>
    <p>This is my game page.</p>
</body>
</html>

PhaserJs

It is time to add the PhaserJs library in our folders. To do so, visit the phaser JS website. There are many ways to download the library, either by npm command, or by cloning the repository from Git.

After downloading the library, please place the minified file “phaser.min.js” in the external folder to have it ready to be used in our next post.

Conclusion

Our server is now running (by using the command above) and we can access out newly created server by accessing “localhost:880” in our web browser.

This post was needed to set the scaffolding for out game.

 

The curse of unfinished side projects

Side projects

If you are a developer, you have surely once in your career, started a little side project either because you had a “great” idea, or because it was a very gloomy rainy day outside and never finished it. In many industry, included the IT one, this is called “the curse of unfinished side projects”.

This comic, is probably one of the most shared across the social media, and it summarise this topic perfectly.

side projects comics
side projects comics

Many people see this has a complete failure, a waste of time and energy, but I see it differently and in this post I will share my idea with you.

No idea is a bad idea

Side projects are hidden pearls. It may be time wasted for many, but in reality any minute spent in a side project is worth way more than a minute spent in your day to day routine. Maybe after spending a night coding an horror game, you realise that it is not for you, or spending your two weeks holiday on the perfect APP made you realise that it wasn’t that perfect or unique, but all this time has an unique purpose. It forces you to think outside of the box, it brings you into unfamiliar ground, and forces you that focus and solve a problem after another, and this is what make this time unique.

The power of a side project does not live within it final product, but in the process required to achieve every small step. It is a free invaluable learning progress.

Since using a scrum methodology in work, I have started to retrospect (scrum retrospective) any work I do, that is a small one day project or a month long. I try to analyse all my actions as often as possible. This helps me understand what need improving and what really could be avoided in the future.

Share the knowledge

Too often, this unfinished side project are not shared with colleagues and family. We too quickly discard these to be a waste of time, without actually having other people opinions and I have learned in recent events that the power lies in sharing these ideas with people, side project are not always left unfinished just because we are lazy, but it may be because we have a full time work and a family to look after, and not enough time to spend on them. But this does not mean that it was the wrong idea or that it should not be brought forward.

Side project are usually created when our body produces an overwhelming dose of adrenaline after having an idea and this is what enable us to stay awake all night.

This is not sustainable, and sharing the information with other could actually help you. First, speaking with others and getting their opinion could actually make you realise that the idea, was not that silly overall and build some more adrenaline. Then, having open discussion with people and keep them updated will actually help you in setting a routine to continue to work on the project. Lastly, it could actually help you find some support, that may be just morale, technical or another pair of hand to share the work.

One in a million

So far we have spoken of unfinished work, and given enough reason to continue to have this small experience. But what if, the project you started this weekend is really its the “one in a million” project that is not going to be left unfinished.

This is another great aspect of side projects, there is always a possibility of creating something that is actually worth all sleepless night. That could one day help you create the next unicorn company (definition of unicorn company).

Conclusion

This blog and website started with a side project, a big feature implemented in the company I work was originally a side project knowledge, and a close friend is actually leaving the dream on what was a side project.

Side project are hidden pearls, we just need to learn how to harvest them. With a bit of organisation and help from others, these projects could actually turn in something tangible and useful.

Javascript Class: ECMAScript standards

 Javascript class

Using javascript class will really improve your code readability, structure and making it shareable with others. ( see my other post: Coding standards: Meaningful Names in Javascript).

For many back end developers, this post would have probably been written over 10 years ago, as classes have always been present in many programming language ( c++, c# and java, etc..). Classes in javascript on the other hand, have just recently been introduced in the ECMAScript 6 release of 2015 and have not yet hit developers keyboards.

This post is aimed aimed to give an introduction to classes and it does not go in many details.

ECMAScrips for Javascript and its advantages

JavaScript does not have the best reputation amongst coding languages, but finally after the long waited version of the ECMAScript standard and good browser support, there is some light at the end of the tunnel, and it is time to deep into the enormous amount of changes that made into the standards.

In recent years, JavaScript developers have been busy creating a multitude of “hacks” and libraries to help us fulfil lack of features that made it hard produce a clean and structured code.

In June 2015 the ECMAScript standards 6 have finally provided a multitude of improvement to one of the most used language in the world, followed by a much smaller release (ECMAScript 7 in June 2016).

ECMAScript 6, took over 4 years to reach our desks, but it didn’t fail to impress and with current browsers finally introducing support for most of the changes, developers are now ready to get their hands dirty and help to improve JavaScript reputation.

Browser Support

Browser support has recently made a fantastic improvement, giving us all a chance to start and implement the great majority of the ECMAScript standards, without worry.

At the time of this post being published (June/2107) the support on desktop is almost complete ( click for full support table):

Edge

FireFox

Chrome

Safari

IE11

As shown by the table above, the support on desktop browser is quite complete, except the odd IE11 with an unacceptable level of support below 15%.

For mobile the situation is quite similar:

Android

iOS

Chrome

Almost full support for the most common browser except on android where just a quarter of features are supported.

Classes Before ECMAScript 6

Even if Javascript class have not been precisely available, developers across the countries have implemented them by using functions, scope, prototype and many other method. This has lead to a multitude of different approaches being adopted by programmers, making the dream of having a possible “standards” a myth.

In this post we will start from an existing small “class” written before the ECMAScript 6, and then implement the newly introduced “classes features” to show the power and structure that they provide to your code.

The code below is an algebra helper for rectangles.

Rectangle
 
var rectangle = function(width, height){
    var self= {};
    self.width = width,
    self.height = height;
    
    var calculateArea = function(){
        var area = 0;
        area = (self.width * self.height);
        return area;
    }
    var calculatePerimeter = function(){
        var perimeter = 0;
        perimeter = (self.width + self.height) * 2;
        return perimeter;
    }
    var getHeight = function(){
        return self.height;
    }
    var setHeight = function(height){
        self.width = height ;
    }
  
  return {
    calculatePerimeter: calculatePerimeter,
    calculateArea: calculateArea,
    getHeight: getHeight,
    setHeight: setHeight
  }
};

Classes in ECMAScript 6

In this section we are going to update the above code to use the javascript class feature.

Class

The first thing that we will have to do is create a base class called rectangle.

base class
 
class rectangle{
    
}

Contructor

Then we will create a constructor. In the previous version of Javscript to emulate the constructor we would have had to create an init function or a self calling function within the method. ( none of this example is shown above as this cover the basic to assign some values).

javascript constructor
 
  constructor(width, height){
 this._width = width;
 this._height = height;
 }

Getter and Setter

Our class is starting to take share, we will now implement the GET and SET methods

Javascrtipt get methods
 
   get height(){
        return this._height;
    }
    set height(height){
        this._height = height;
    }

This methods have been introduced in the ECMAScript 2015. They are commonly used across different programming language and do not require a function call to be initialised. An example usage of the above would be:

get and set
 
var r = new rectangle(10, 5);
r.getHeight;// Output 5
r.setHeight = 10
r.getHeight;//Will output 10

Methods declaration

Class methods have not changed and the declaration is very similar to the one showed in the initial javascript example. The main difference to note is that every method declared within a function will actually be set to PUBLIC. There are rumours of the implementation of public variables and methods for the next ECMA release ( Javascript new private class field). There are currently 4 different “solution” to make standards private methods, and they are all out of the scope of this post.

Method declared within a class will not require the “function” word, and do not require to be returned or specifically made available as they will be available as part of the object immediately after initialisation. Our example will be:

class methods
 
    calculateArea(){
        var area = 0;
        area = (this._width * this._height);
        return area;
    }
    calculatePerimeter(){
        var perimeter = 0;
        perimeter = (this._width + this._height) * 2;
        return perimeter;
    }

Conclusion

This post is aimed at sparkling some curiosity, and give just a small definition of javascript class. The final result is:

final
 
class rectangle{
    constructor(width, height){
        this._width = width;
        this._height = height;
    }
    get getHeight(){
        return this._height;
    }
    set setHeight(height){
        this._height = height;
    }
    calculateArea(){
        var area = 0;
        area = (this._width * this._height);
        return area;
    }
    calculatePerimeter(){
        var perimeter = 0;
        perimeter = (this._width + this._height) * 2;
        return perimeter;
    }
}
var r = new rectangle(10, 5);
r.getHeight;// Output 5
r.setHeight = 10
r.getHeight;//Will output 10

Classes are maybe still not fully ready for big production environment ( mainly because of the absence of a private field), but we should start to use them to get confident in using them when time comes. There are still some amazing features like inheritance ( that has not been covered in this post) that make class worth using.

I personally like the use of class because they force to structure the code differently. They put a big distinction between normal functions and big chunk of work and are perfect to get around Object orientated programming.

I will keep posting my finding on the ECMAscript 6 and future release as for my opinion this is the real future of javascript.

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