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Finding a JS bug using chrome developer Tools

Another issue was filed in the cube-roll project, Issue #4 which was a problem with the games score not updating. It turned out to be a small fix but I wanted to go through how I found where in the code the bug was.

I first started the game and duplicated the problem.

I then looked through the code and find what I think gets called when I get a point. I found that line 90 of the world.js file is where the logic for updating the score was.

After finding the area of code where I thought the problem could be, I opened the developers tools in chrome and then I navigated to the sources tab. In the sources tab I navigate to the file I want world.js. I can now setup breakpoints, after that I started the game and duplicated the problem again. This time since I setup the breakpoints the game pause on the breakpoint and I could look at the values of the data in the developer tools.

As you can see in Figure 1 this is what happens when you trigger a breakpoint.

A snippet of the chrome developer tool
Figure 1

After doing the above a few times in multiple areas of the code, I located the line of code with the problem. Inside, hud.js there is the function setText() that is called from line 98 of the world.js file.

Inside setText() I found the below typo:

setText(id, text){
    this.elements[id].test=text; // .test should be .text
    this.redraw=true;
}

Now that I found the problem I was able to fix the typo and submit a PR:

https://github.com/mklan/cube-roll/pull/5

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Fixed restart bug in Three.js game cube-roll

While I was looking for a game to help develop, I found the game cube-roll on github.

The bug I fixed was issue 1 : cannot restart game, the problem occurred after you play a round, the game will freeze and you were not able to restart it.

This turned out to be a fun project to work on, it was challenging at the start. Since, I have never worked on a game before so I didn’t know what the code was doing. But after looking through the code for a bit, I found out that the game was using Three.js. Three.js is a javascript 3D library I was able to learn a bit more from their docs on what the code was doing.

After learning the code, I found out were the problem was, it turned out most of the code was already their it was just not working correctly. The problem resided in the main function, when the game is over and the user pressed enter, it would cue a .once() command in the main. Originally it just called the main again to restart the game. The problem was the game never got cleared so the old game was still running.

In order to fix the issue I used the following code, it first calls the constructor on the world object hence clearing and restarting the game. I then pass that world object back to main to restart the game. The important factor was I am not ever creating a new world just resting it.

sync function main(connectToServer, world = undefined) {
  renderPause = true;
  if(!world){
    world = await new World();
  }
  world.playerControls.once('enterWhenGameOver', async () => {
    await world.constructor();
    main(false,world);
  });
  if (connectToServer) {
      server = await initServer;
      server.on('clientKeyUp', key => {
        world.playerControls.processRemoteControl(key);
      });
  }
  renderPause = false;
  if (!tickingStarted) {
    tick(world, server);
  }
}

The reason I do not want to loose the world object is because it is being used in the tick() function. The tick function is what refreshes the game it contains a reference to the world object, so that is the reason I needed to keep the same instance of world object when the restarts.

function tick(world, server) {
  requestAnimationFrame(() => tick(world, server));
  if (!renderPause) {
    tickingStarted = true;
    world.update();
    world.render();
    server && server.stream();
  }
}

Here is a link to my PR: https://github.com/mklan/cube-roll/pull/3

 

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Maintaining a GitHub Project

Wow I now have a much better understanding of the life of a project maintenance, after this week.

So, a few classmates have now joined the NodeChat Project, the week started simple by me posting a bunch of issues for everyone to work on. But, once they started to work in the project, they started to post their own issue’s. They ran into thing’s that being the one who wrote most of the code, I didn’t really think about.

For example, the readme file I didn’t need it so it was very outdated and simple. So, I needed to update that so people could more easily start working. Also, I added a contributing file which explain’s a few more thing’s. updated docs.

Another example, was the folder structure was outdated, we were working inside a folder while the root contained the original project before I started working on it, so there were a bunch of files kinda not really doing anything. And we also had the server inside the same git repo. Apparently this is very confusing, another thing that I got used to and learned to ignore, which wasn’t good for new contributors joining the project. We have now gotten ride of all the old code and moved the server into it’s own repo. So now the react app is alone it the main repo, which make a lot more sense for new contributors.

Lot’s of change’s happened over this past week on the OTRChat Project. I have now had a taste of what managing a project looks like and I am only working with 4 people, can’t image large project with 100+ contributor’s. As with everything you start small and work toward something big.

 

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Hacktoberfest Week Two – React and Push.js

In this week of Hacktoberfest, I added push notifications to the Node Chat project in my most recent Pull request. I used the Push.js library in order to accomplish this task. Well learning how to do this, I din’t find much documentation on using Push.js with React so I put together a small tutorial for today’s blog.

Integrating Push.js with React

Natively, there is currently no solution to use Push.js with React. In order to use Push.js with react you have to use it as an external libraries. Below is how I added Push.js to React as an external library.

First step:

Include the script file in the main “index.html” file for your app.

I used a CDN to do this:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/push.js/1.0.7/push.min.js"></script>

Second step:

Import Push.js into your file.

Put the following line at the top of the .js file you want to use Push.js in.

import * as Push from "push.js";

After importing Push.js you can now create push notifications inside your react app.

Here’s an example of how to create a notification in a react component.

notify(){
 Push.create("Hello world!", {
     body: "Thanks for reading my Blog!",
     timeout: 5000,
     onClick: function () {
         window.focus();
         this.close();
     }
 });
}

 

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Hacktoberfest Week One

In my first week of Hacktoberfest I started off without any particular project in mind. I had a few ideas of what I wanted to work on, so I started by searching GitHub for a project. I was looking for something using JavaScript or C++.

After searching for a while I came across a application called NodeChat. In Issue #11 for the NodeChat project the owner asked for someone to move the public site over to React. Having used React, Node.js and Socket.IO I asked in the issue if I could do this.  After, that I started my work on the React app to replace the JQuery version that was previously used in the project.

Making a chat app using React

I started off with some project designing. I needed to figure out how I wanted to organize the react app. Also, I had to go through the existing JQuery file to get a better understanding of what the project is doing.

I decided on the below structure for the app.

    • App
      • This component is the core of the app were the Login Page is called and is currently were all the css and assets are located.
    • LoginPage
      • This component handles new and previous user login’s.  And handles displaying the login page or the chat page.
    • ChatPage
      • This compenent handles all the functionality of the chat.

Currently the flow of the app is as follows the app page displays the Login page. The login page creates a new user or uses a previous user then the Login page decides when to display the Chat page.

A update I think I will do at some point would be to make it so the App page receives props back form the Login page. That would instruct the App page when to display the Chat page. I think this would be a bit cleaner code.

There is still a bunch of stuff that need’s to be finished but at the moment the app is working on a basic level. I am hoping to get most of the bugs fixed as soon as I can.

I think this will be a good project for me over Hacktoberfest and probably after.

Here’s the link to my first PR of Hacktoberfest .

Below is the 2 class definitions for Login Page and Chat Page and I added a small comment about each function. Full Code available here.

class LoginPage extends Component {
    constructor(props) {}
    // Checks if user pressed enter key to submit there message.
    enterKeyPress(e) {}
    // Used to manage the State of the input field on the Login Page.
    setUsernameInput(event) {}
    // Calls checkIfPreviousUser()
    componentDidMount() {}
    // Sets the username 
    setUsername() {}
    // Checks current user is a previous user or calls setUsername() if not.
    checkIfPreviousUser() { }
    // Tell the server that we've had a user join
    userJoin() {}
    // Holds the content's of the Login Page
    displayLogin() {}
    // Render Login Page if not loged in or Chat page if Logged in
    render() {}
}


class ChatPage extends Component {
    constructor(props) {}
    // Calls greetUser() and Lisen's for New Chat messages.
    componentDidMount() {}
    // Displays Greeting message.
    greetUser() {}
    // Checks if user pressed enter key to submit there message.
    enterKeyPress(e) {}
    // Used to manage the State of the input field on the chat app.
    setChatInput(event) {}
    // Send's the message to the server.
    sendMessage() {}
    // Recieve's the chat messages from the server.
    addChatMessage(data) {}
    // Used to handle images(not tested).
    parseMessageText(inputString) {}
    // Used to handle images(not tested).
    imageFile(filetype) {}
    // Used to handle images(not tested).
    getFileType(inputString) {}
    // Used to handle images(not tested)..
    imageLink(inputString) {}
    // Used automatically scroll the page.
    scrollToBottom() {}
    // Render page content.
    render() {}
}