Category: javascript

I am making a brick breaker game in JavaScript. I want to add continuous collision detection.
Such that if the ball(circle) were to collide with a brick(rectangle) between frames the ball’s position and velocity update based on where they would have collided (let collidePointX = BALL.x – BRICK.x;).

It seems that the way to do this is draw collision from a ray of (the ball’s velocity vector + the ball’s radius) but that ray’s collision doesn’t reflect where the ball’s x,y would have been if it collided naturally.

to reiterate I need to determine the x&y collide points (let collidePointX = BALL.x – BRICK.x;) when my ball would collide between frames.

How do I solve this?

Is there terminology for this?

Is there a library that solves this?

Is the solution different for (circle/rectangle) vs.(circle/circle) collisions?

I’m super new and feel way over my head with this one. It’s proving difficult to Google.

console.log(/d[x/+‑]{1}‑$/.test('56+-'))
console.log(/d[x/+-]{1}-$/.test('56+-'))

Two Regex seem totally same, but I get two different result in Chrome Console

why?

I don’t know the Uncaught SyntaxError: Unexpected token ‘if’

var fee = Number($(this).find('.fee').text());

if(subtotal <= 9999){
  fee = 330;

}esle if(subtotal <= 29999 && subtotal > 9999){ //error in here
  fee = 440;

}esle if(subtotal <= 99999 && subtotal > 29999){
  fee = 660;

}esle (subtotal <= 300000 && subtotal > 99999){
  fee = 1100;
}

console.log(fee);

For a div with css of {padding:10% 10px 20% 10px;} I need to be able to retrieve via JavaScript the padding as it is set but window.getComputedStyle(myelement).getPropertyValue(‘padding’); returns different results.

Firefox = “10% 10px 20% 10px”

Chromium = “59.8839px 10px 119.768px 2px”

Is there any other way to retrieve this info so it gets the % values and not the elements current state px value?

http://jsfiddle.net/o1jhbn9f/1/

var div = document.getElementsByTagName('div')[0];
console.log(window.getComputedStyle(div).getPropertyValue('padding'));

In my ReactJs project im using the Authentication feature of Firebase , when i try to register a new user to the authetication data base it fails and i get the following message in my console , will anyone explains how fix that ?

Because a cookie’s SameSite attribute was not set or is invalid, it
defaults to SameSite=Lax, which prevents the cookie from being sent in
a cross-site request. This behavior protects user data from
accidentally leaking to third parties and cross-site request forgery.
Resolve this issue by updating the attributes of the cookie: Specify
SameSite=None and Secure if the cookie should be sent in cross-site
requests. This enables third-party use. Specify SameSite=Strict or
SameSite=Lax if the cookie should not be sent in cross-site requests.

I have been trying to figure why none of the JS I try to echo is echoing. To summarise my project I have a function which calls a PHP file and then the PHP file sends information back. It can send information which is not in JS but as soon as I try JS nothings come about. I have even tried a basic console.log(); and still nothing.

Does anybody have an idea on why this is?

Below is the file which is calling.

<html>
<link rel="stylesheet" type="text/css" href="styles.css">
<div class="HogMainContent">
<button name="Subtract" onclick=subtract()>Previous Game</button>
<button name="Add" onclick="add()">Next Game</button>
<div id="insertion"></div>
<script>
var count = 0;
function send(item) {
  const xmlhttp = new XMLHttpRequest();
    xmlhttp.onload = function() {
      document.getElementById("insertion").innerHTML = this.responseText;
    }
    xmlhttp.open("GET", "gather.php?q=" + item);
    xmlhttp.send();
}
function subtract() {
  count--;
  send(count);

}
function add() {
  count++;
  send(count);
}
</script>
</div>
</html>

Below is the file which is being called. This is where no JS is working.

<?php
$host = "localhost";
$username = "root";
$password = "";
$db = "ia2";
$link = mysqli_connect($host, $username, $password, $db);
if($link === false) {
  die("Error: Couldn't Connect." . mysqli_connect_error());
}
$q = $_REQUEST["q"];
$sql = "SELECT * FROM vgsales WHERE `Rank`=$q";
if($result = mysqli_query($link, $sql)){
  if(mysqli_num_rows($result)>0) {
    while($row=mysqli_fetch_array($result)){
      echo $row['Rank'];
      echo $row['Name'];
      echo $row['Platform'];
      echo $row['Year'];
      echo $row['Genre'];
      echo $row['Publisher'];
      echo $row['NA_Sales'];
      echo "
      <script type='text/javascript' src='https://www.gstatic.com/charts/loader.js'></script>
      <div id='myChart' style='width:100%; max-width:600px; height:500px;''></div>
      <script type='text/JavaScript'>
      google.charts.load('current', {'packages':['corechart']});
      google.charts.setOnLoadCallback(drawChart);
      function drawChart() {
      var data = google.visualization.arrayToDataTable([
        ['Sales Region', 'Number of Sales']
        ['NA Sales',". $row['NA_Sales']."],
        ['EU Sales',". $row['EU_Sales']."],
        ['France',". $row['JP_Sales']."],
        ['Spain',".$row['Other_Sales']."],
      ], true);
      var options = {
        title:'Game Sales". $row['Name']."'
      };
      var chart = new google.visualization.PieChart(document.getElementById('myChart'));
      chart.draw(data, options);
      }
      </script>
      ";
    }
    mysqli_free_result($result);
  }
}
else {
  echo "Error: Could not execute $sql" . mysqli_error($link);
}
mysqli_close($link);
?>

I am building a project where I have to store the URLs in a database. Is there any way to escape URLs? How to store and retrieve it efficiently using Javascript?

I know similar questions have been asked many times before, but most results are for older versions and the API has changed a lot. I could not find code for 3.5+ that “just works”.

I’m wondering if there’s a better way to achieve what I want.

I have multiple datasets mapped to one y-axis in chart.js. This works well as we chart them to compare them across time (x-axis) and value. The y-axis expands based on all datasets.

I had a request to simply duplicate the labels so they show on both the left and right side. This does not seem to be simple as axes are mapped to datasets one-to-one.

Using https://stackoverflow.com/a/58525418/2060441 and updating it for my version of chart.js I came up with the below. Is there a better way? It feels very clunky. Notably once the chart options become an object, updating the min/max directly doesn’t appear to work so I have to replace it wholesale.

// add a dummy dataset, use legend.labels.filter to stop them showing
datasets.push({ yAxisID: 'yAxis2' });
            
forecast_chart.data.datasets = datasets;

minTick = forecast_chart.scales.yAxis1.min;
maxTick = forecast_chart.scales.yAxis1.max;

forecast_chart.options.scales.yAxis2 =
{
    type: 'linear',
    position: 'right',
    min: minTick,
    max: maxTick,
    ticks:
    {
        stepSize: 50,
    
    };
};
forecast_chart.update();
forecast_chart.resize();

I established a model for Posts and created a POST request handler. As you can see, if it works, it will send a message back saying “nice” to the user who made the request.

Using Postman on desktop, I try to make a POST request with the necessary body, but it always arrives at a 500 error. Can someone explain why or is there something I’m missing?

const router = express.Router();
const Post = require('../models/Post')

router.get('/', (req, res) => {
  res.send('We are posts')
})

router.post('/', async (req,res) => {
  const post = new Post(req.body)

  try {
    await post.save();
    res.send("nice");
  } catch (error) {
    res.status(500).send("error");
  }
})



module.exports = router;

app.js

require ('dotenv/config')
const express = require('express');
const mongoose = require('mongoose')
const app = express();
const postsRoute = require('./routes/posts')

app.use(express.json())

app.use('/posts', postsRoute)

app.get('/', (req, res) => {
  res.send('We are home')
})

// Connect to DB
mongoose.connect(process.env.DB_CONNECTION,  {
  useNewUrlParser: true,
  useFindAndModify: false,
  useUnifiedTopology: true
},() => {
  console.log("connected to db")
})

I am using MongoDB Cloud, by the way.

I am using a package that is getting this error an I have figured out haw to reproduce it.

Basically assignment of a new Error() to a variable works, but then when you try to reassign it – it actually throws an error. Why does this happen?
Here is an example use case:

// Filename: test.js
var myError = new Error("Original Error.");

if (true) {
  myError = new Error("New Error!");
}

$ node test.js – executes no problem.

$ node
> .load test.js

^ This produces the error. However the package I am using does this similar pattern and gets the same error, but that is obviously not something I am doing in the node shell.

I have also found out that simply re-declaring the variable, instead of reassigning it will not invoke the error.

Any thoughts on this?

I have a script that enables a button if at least one checkbox is selected and a checkbox selects all.

The problem is that I can’t make it work correctly, when I select the checkbox select all it activates the button but if I uncheck it it is not deactivating.

The delete checkboxes are working correctly the problem is in select all

var checa = document.querySelectorAll(".toggle");
var numElementos = checa.length;
var bt = document.getElementById("btn");
for(var x=0; x<numElementos; x++){
   checa[x].onclick = function(){
      // "input[name='toggle']:checked" conta os checkbox checados
      var cont = document.querySelectorAll(".toggle:checked").length;
      // ternário que verifica se há algum checado.
      // se não há, retorna 0 (false), logo desabilita o botão
      bt.disabled = cont ? false : true;
   }
}

//---------------------------------------

var roles = {
    checkall: {
        delete: true
    }
};

 $('.role').click(function() {
     var result = {};
     $('.role').each(function() {
         if (!$(this).prop('checked')) return;
         var role = $(this).attr('id');
         $.extend(result, roles[role]);
     });
     $('.perm').each(function() {
         var perm = $(this).attr('id');
         var chk = (perm in result);
         $(this).prop('checked', chk);
     });
 });

<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet"/>
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="container card m-4 p-3">

<div>
<input class="role toggle me-2" type="checkbox" name="toggle" id="checkall"/>Select all
</div>
<hr />
<div class="mb-1">
<input class="perm toggle me-2" type="checkbox" name="toggle" id="delete"/>Delete 1
</div>
<div class="mb-1">
<input class="perm toggle me-2" type="checkbox" name="toggle" id="delete"/>Delete 2
</div>
<div class="mb-1">
<input class="perm toggle me-2" type="checkbox" name="toggle" id="delete"/>Delete 3
</div>
<div class="mb-1">
<input class="perm toggle me-2" type="checkbox" name="toggle" id="delete"/>Delete 4
</div>
<div class="mb-1">
<input class="perm toggle me-2" type="checkbox" name="toggle" id="delete"/>Delete 5
</div>
<div class="mb-1">
<input class="perm toggle me-2" type="checkbox" name="toggle" id="delete"/>Delete 6
</div>
<hr />
<div>
    <button type="button" class="btn btn-danger btn-sm" id="btn" disabled> Delete selected</button> 
</div>
</div>

It seems running prettier ignores embedded style tags (and code) inside backticks:

import Base from './Base.js';

class NavBar extends Base {
    constructor() {
        super();
    }

    static get name() {
        return `${this.ns}-navbar`;
    }

    connectedCallback() {
        this.attachShadow({ mode: 'open' });
        this.shadowRoot.innerHTML = `
    <style>
      .navbar {
        margin-top: 1rem;
        display: flex;
        justify-content: center;
        align-items: flex-start;
      }
      
      .navbar a {
        margin: 0 .4rem;
        text-decoration: none;
      }    

        .navbar a.active {
            font-weight: 700;
            text-decoration: underline;
        }
    </style>
    <nav class="navbar">
        <a href="/recent.html" class="${this.isCurrentPage('/recent') ? 'active' : ''}">recent</a>
        <a href="/popular.html" class="${
                    this.isCurrentPage('/popular') ? 'active' : ''
                }">popular</a>
        <a href="/tags.html" class="${this.isCurrentPage('/tags') ? 'active' : ''}">tags</a>
        <a href="/" class="${this.isCurrentPage('/$') ? 'active' : ''}">home</a>
    </nav>
`;
    }
}

customElements.define(NavBar.name, NavBar);

.prettierrc:

{
    "useTabs": true,
    "singleQuote": true,
    "trailingComma": "none",
    "printWidth": 100,
    "arrowParens": "avoid"
}

Command: npx prettier -w .

Is there anyway to get prettier to format the code inside backticks?

I want to add popups (movemouse) from two Mapbox Studio tilesets to HTML code. This tileset are in the same map:
*Tileset 1: https://studio.mapbox.com/tilesets/mapanaval.1ogp366t/#10.95/-34.6229/-58.4428, atributes[Nombre, Tipo]
*Tileset 2: https://studio.mapbox.com/tilesets/mapanaval.5f95hcr9/#0.86/0/-58.4 , atributes[CALLE, TIPO]

¿What is the correct code to add popups to the next html?

https://raw.githubusercontent.com/datatto/Mapa-Naval/main/mapa_v1.html

Thanks!

I am having issues figuring out how I can go up a directory from my server running to run a python script. I am able to run a python script using the child process, {spawn}, however, I am unable to go up once, to the parent directory to run the python script.

I’m quite new to using async/await and am having some problems getting a function to work.
I have a function getRatings that maps through data returned from a call to my firebase firestore.
I’m wondering how I use async/await to return the data, because at the moment when I console.log the output of the function, I get

Promise {}

Here’s the function in question, filteredVenue represents the data returned from the firebase call:

  const getRatings = async () => {
    let arr = [];
    await filteredVenue.map((venue) => {
       return venue.reviews.map((ratings) => {
        const ratingsObject = {
          food: ratings.ratingFood,
          service: ratings.ratingService,
          value: ratings.ratingValue,
          atmosphere: ratings.ratingAtmosphere,
        };
        arr.push(ratingsObject);
      })
    })
    const newObject =  {
      food: arr[0].food,
      service: arr[0].service,
      value: arr[0].value,
      atmosphere: arr[0].atmosphere,
    };
    return newObject;
  };

  const venueRatings = getRatings() 

  console.log(venueRatings) // yields a pending promise

Any suggestions?