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CSS HTML5 Javascript Svelte SvelteKit

I Wrote a (Technical) Book and So Can You

I was approached to write a book about #SvelteKit because I had written about it here. This post outlines my experience writing a technical book, from start to finish.

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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? πŸ€” 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 πŸ₯³!
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.

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Automation CSS HTML5 Javascript Linux Mobile PHP Programming Security Server Svelte WordPress

BUY! BUY! BUY!

I’ve been writing on this blog for nearly 9 years and I’ve learned so much since I started. The style and the content have come a long ways and I cringe every time I read old posts thoroughly enjoy seeing how I’ve grown as a developer. I’ve interacted with people that I never would have had the chance to otherwise. It’s been a wonderful learning experience.
While my intentions have always been for this site to exist as a sort of journal/wiki/knowledgebase/playground, I’ve always secretly wanted to become a billionaire tech influencer. And now you can help me achieve that goal by buying my merchandise!
BUY! BUY! BUY!
By purchasing merchandise from my shop, you can support this site financially, by giving me real money that you’ve earned for your “hard work.” While donations are always appreciated, I understand that you may want something in return; something tangible, something you can see and smell, something to keep you comfortable while you cry yourself to sleep. And since nobody actually donates to strangers on the internet, I opened a shop.

All of the designs are completely original and there are many, many more to come. The pricing is affordable for all budgets and will only expand with more options. Be sure to check posts here often by following the social media channels or the RSS feed. There may just be coupon codes hidden in future posts πŸ˜‰.
So if you’re ready to showcase the fact that you know what HTML is and like the look of monospaced fonts, then you should go checkout the new closingtags merch shop. Once you’ve got the closingtags swag (closingswag πŸ€”), be prepared to have people you barely know ask if you “work with computers” or to tell you about their genius new app idea.
Don’t forget to buy, buy, buy!

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CSS HTML5 jQuery Mobile PHP WordPress

Developing with Vagrant

Recently, I’ve been trying to find ways to speed up my development time, and I came across a great video showcasing Vagrant. I could spend a lot of time writing a bunch of mumbo jumbo here for you to read, or you could just watch the video that explains it a thousand times better than I would ever be able to.

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CSS HTML5 jQuery PHP WordPress

DemocracyOS

It’s been pretty slow on the web development front for me lately, but I have discovered something new and interesting. It’s called DemocracyOS. What is DemocracyOS? Oh, I’m so glad you asked. Well it’s an open-sourced platform that aims to bring democracy back into the hands of the people in a way that makes voting on almost anything, very simple.
Just recently, we had some elections here in the US (Nov. 4th, 2014) and supposedly, Republicans took back control of both the House and the Senate because so many young people didn’t turn out to vote. What DemocracyOS intends to do, is bring the voting to you. No more waiting in lines at the polls, trying to get away from work, attempting to figure out where you’re supposed to go to vote, or filling in the circles ever so perfectly on an outdated technology (paper).
It’s supposed to be as simple to install and use as WordPress, although I haven’t quite gotten that far yet. I’ll keep the blog updated with my findings though. Check it out at Github hereΒ or the main site here.
And if you want to chat about this stuff, hit me up on Twitter @awebdevguy.

Categories
HTML5 jQuery

HTML Games

Whoa. I just discovered this super easy way to build HTML5 web games, where a ton of the heavy lifting is already done for you. Seriously, go check out what the guys and gals over at Photon Storm are doing and check out Phaser