2025-09-29 15:37:31
Hey friends!
We're going to be waking up this week because September is ending! But until then, let's kick back with some content.
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The Best CSS Unit Might Be a Combination
JSON is not JSON Across Languages
You may be looking for a useSyncExternalStore
Stop using .reverse().find(): meet findLast()
This week was a fairly offline week of cleaning around our home, potty training my toddler (highly recommend this book if you ever need some tips, it has worked super well for us), and just being with family and friends. My inbox is suffering, BUT it's been good for my brain.
That being said... I did mess around a bit with my mobile writing setup, and it's been really nice! I want to mess with it more when I can.
No sponsor this week (the economy, amirite?), but I'm still grateful you're looking here. Have a good week, check out Ductts, check out PocketCal, and dream of a calmer tomorrow.
I'd appreciate deeply if you share this newsletter with your friends, coworkers, or anyone you think might like it. Or who might hate-read it. Or who might just be bored and want another email in their inbox every week.
<3
Last week, I had you identify numbers as abundant, deficient, perfect, or amicable! YOU are the perfect ones, Sergio, Amine, Adam, George, Usman, Andrew, Pedro, Elke, David, Marco, Victor, Gavin, John, Jonathan, Neefertiti, Ten, and Paul!
This week's question:
Given the non-negative integer n , output the value of its hyperfactorial. Don't worry about outputs exceeding your language's integer limit.
Examples:
> hyperfactorial(0)
> 1
> hyperfactorial(2)
> 4
>
> hyperfactorial(3)
> 108
> hyperfactorial(7)
> 3319766398771200000
(you can submit your answers by replying to this email with a link to your solution, or share on Bluesky, Twitter, LinkedIn, or Mastodon)
Fat Bear Week is here early, and the bears are fat and playful
Always invite Anna
filofax original (personal size) unboxing, setup & flip-through (video)
OwLab Spring | blu4t | DROP+MiTo Keysterine (video)
Anyone can make a pun... but only a parent can nurture it until it's fully groan!
That's all for now, folks! Have a great week. Be safe, make good choices, and stay hydrated!
Special thanks to Ezell, Ben, Kinetic Labs, Marta, and Flora for supporting my Patreon and this newsletter!
cassidoo
website | blog | github | bluesky | twitter | patreon | twitch | codepen | mastodon
2025-09-22 16:53:03
Hey friends!
I hope your had a good week! Mine flew by, and I had a great time. I'll tell ya more about it below! Let's gooo.
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All 197 entries submitted to js13kGames 2025
The History of Themeable User Interfaces
React Won by Default - And It's Killing Frontend Innovation
BlueSky Likes Components
This week I saw Lea Salonga in concert! She was spectacular.
She sang not only her well-known hits (like "Reflection" from Mulan, "On My Own" from Les Misérables, and "A Whole New World" from Aladdin), but also a bunch of other songs from various movies and Broadway shows.
Her tour is called, "Stage, Screen & Everything In Between" and it is perfectly that. She did Disney medleys (I practically levitated when she transitioned between "Colors of the Wind" to "Let it Go"), and songs made famous by movies like "My Heart Will Go On" from Titanic, and "A Million Dreams" from The Greatest Showman.
I love musicals (on stage and off), so this felt like the perfect show for lil ol me, and I just loved it!
Stop testing your platform in prod---simulate it!
Applied Computing Research Labs built SimKube to help you test changes to your Kubernetes platform locally instead of in production. With SimKube, you can replicate your entire production Kubernetes environment on your laptop (or in your CI pipeline) and "shift left" your platform development. Want to know if your new autoscaling policy leaves pods stuck in Pending? Want to make your boss look good and save some money with better bin-packing? Want to ship a change on Friday afternoon without making your on-call mad? Simulate it first!
We've used SimKube for all these scenarios and more. Read a case study about our recent work with Astronomer, or contact us to learn how SimKube can make your Kubernetes platform better.
Last week, I had you analyze baseball scores! Home run Gavin, Ender, György, Juliano, Rafael, Paul, Ten, Taylor, David, Elke, and Stephen!
This week's question:
Write a function that determines if a number is abundant, deficient, perfect, or amicable. (Thanks Raymond for this one!)
Examples:
whatKindOfNumber(6)
> 'perfect'
whatKindOfNumber(12)
> 'abundant'
whatKindOfNumber(4)
> 'deficient'
(you can submit your answers by replying to this email with a link to your solution, or share on Bluesky, Twitter, LinkedIn, or Mastodon)
Their schools banned phones. Out came the iPods and cassette players.
Teaching Lettering to Third Graders
I made a mechanical laptop (video)
I didn't bring my son to a museum to look at screens
Why did the chicken become a chef?
Because it has im-peck-able taste!
That's all for now, folks! Have a great week. Be safe, make good choices, and sit up straight!
Special thanks to Ezell, Ben, Kinetic Labs, Marta, and Flora for supporting my Patreon and this newsletter!
cassidoo
website | blog | github | bluesky | twitter | patreon | twitch | codepen | mastodon
2025-09-15 15:59:06
Hellllooo!
I hope your week was a good one. Mine was tiring (what else is new?) but I had a good time with family and friends. Let's boogie.
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100+ new CSS features from the past 5 years
Why do browsers throttle JavaScript timers?
How I Wish Web Components Worked
Don’t Inherit the Box Model
This week was kind of chaotic in the news, but I was mostly disconnected from it while hanging out with my kiddos, seeing relatives, eating with friends, and watching the k-drama Vincenzo (it's weird and very funny). I think it was good for my brain to not be hyperaware of everything!
I did make a tree visualizer (the data structure, not the nature kind), which was pretty fun. Here it is if you want to check it out!
No sponsor this week (the economy, amirite?), but I'm still grateful you're looking here. Have a good week, check out Ductts, check out PocketCal, and dream of a calmer tomorrow.
I'd appreciate deeply if you share this newsletter with your friends, coworkers, or anyone you think might like it. Or who might hate-read it. Or who might just be bored and want another email in their inbox every week.
<3
Last week, I had you sum up neighboring elements in an array! Awesome work Sreetam, Jonathan, Mike, Collin, Miguel, David, Elke, Muhammad, Victor, Gavin, Paul, Amine, Sergio, Ten, Leyan, and Kaartic!
This week's question:
You are given an array of arrays, where each inner array represents the runs scored by each team in an inning of a baseball game: [[home1, away1], [home2, away2], ...]. Write a function that returns an object with the total runs for each team, which innings each team led, and who won the game.
Example:
const innings = [[1, 0], [2, 2], [0, 3], [4, 1]];
> analyzeBaseballGame(innings)
> {
homeTotal: 7,
awayTotal: 6,
homeLedInnings: [1, 2, 4],
awayLedInnings: [3],
winner: "home"
}
(you can submit your answers by replying to this email with a link to your solution, or share on Bluesky, Twitter, LinkedIn, or Mastodon)
You Need to Be Bored. Here's Why. (video)
How celery salt wound up on the Chicago dog
Fixing the Biggest Problem With Mechanical Keyboards (video)
7 Questions from Aspiring Board Game Designers (video)
All 54 lost clickwheel iPod games have now been preserved for posterity
Roman numeral puns are awesome, and I, for one, will continue to make them!
That's all for now, folks! Have a great week. Be safe, make good choices, and write more!
Special thanks to Ezell, Ben, Kinetic Labs, Marta, and Flora for supporting my Patreon and this newsletter!
cassidoo
website | blog | github | bluesky | twitter | patreon | twitch | codepen | mastodon
2025-09-08 13:26:49
Hey friends!
I hope you had a good week. Mine was busy, but we got to see some family and friends, so that made it worth it! Let's learn.
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Functional custom elements the easy way
CodePen Radio: Hot Trends of 2025
You no longer need JavaScript
CSS overrides without important using layers in Astro components
I went on a major deep dive over the past couple weeks on physical notebook planners for 2026. I saw in some of my social media feeds a bunch of posts about how the Hobonichi planners came out, and was rapidly influenced to think that a physical planner could change my entire life for the better.
...I was then rapidly deinfluenced when I tried to visit Paper & Pencil, a local stationary shop, and the lines for said planners were literally FOUR hours long. FOUR. No?? There has to be a better way??
So anyway, I did not buy a planner, but I learned a lot about that world, which was cool. I also visited Atlas Stationers in person, which was a delightful experience, and if you ever get a chance to shop there (in person or online), they're a lovely, family-owned company here in Chicago!
Think faster than you type? Flow is developer-first dictation that actually gets code. Speak naturally in Cursor, Windsurf, VS Code—even Slack or Notion—and Flow preserves syntax, variables, and context exactly how you’d type them. No typos, no break in rhythm, just… flow.
Why devs love it:
Flow is free up to 2,000 words per week. You normally get 14 days Unlimited—but cassidoo readers unlock an extra 30 days Unlimited free.
Last week, I had you implement a simplified version of the game Battleship! Yo ho Sreetam, Ten, Elke, David, Amine, Scott, and Kaartic!
This week's question:
For an array of numbers, generate an array where for every element, all neighboring elements are added to itself, and return the sum of that array.
Examples:
[] -> 0
[1] -> 1
[1, 4] -> 10 // (1+4 + 4+1)
[1, 4, 7] -> 28
[1, 4, 7, 10] -> 55
[-1, -2, -3] -> -14
[0.1, 0.2, 0.3] -> 1.4
[1,-20,300,-4000,50000,-600000,7000000] -> 12338842
(you can submit your answers by replying to this email with a link to your solution, or share on Bluesky, Twitter, LinkedIn, or Mastodon)
The story of how RSS beat Microsoft
Why All Writing Sounds the Same Now (video)
Through the Eyes of an Angel: New York Photos by Anthony Angel
Banana keyboard
Police have just arrested the tongue-twister world champion.
If found guilty, they'll be given a very tough sentence.
That's all for now, folks! Have a great week. Be safe, make good choices, and get rid of your outdated cables!
Special thanks to Ezell, Ben, Kinetic Labs, Marta, and Flora for supporting my Patreon and this newsletter!
cassidoo
website | blog | github | bluesky | twitter | patreon | twitch | codepen | mastodon
2025-09-01 13:19:52
Hey friends!
August is done, we're through! Finished! Now that September is here, I'll be napping and you can wake me up when September ends. Ha. But anyway, let's learn.
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HTML Partials + Server Reducers: An Alternative to React-Style SPAs
CMYK Concentric Curves
Rolling the Dice with CSS random()
Style your underlines
View Transitions: What Could Possibly Go Wrong?
This was a really exciting week for our family: my husband became a citizen of the United States! The ceremony was great. 95 people were sworn in from more than 40 countries! The judge had everyone applaud for each person's home country, and gave a really wonderful speech about how we are a nation of immigrants, and how we have to work to make our communities better for everyone. I admit when the news is frustrating and overwhelming at times, it's hard to even fathom being patriotic... but this ceremony was an exception. I'm really grateful that we've made it across the finish line after a long journey getting here!
AI is breaking the old rules. Your database has to keep up. MongoDB wasn't retrofitted for AI; it was born for it, handling the messy, dynamic data that AI thrives on. Join MongoDB.local NYC on Sept 17 at the Javits Center for talks, demos, hands-on labs, and networking. Unlock new possibilities for your data in the age of AI. Register here and use code SOCIAL50 to save 50%!
Last week, I had you make a restaurant order summary! Order up Amine, Taylor, Dennis, Miguel, Elke, Joey, Sergio, Stephen, Laasya, John, Nico, and Ten!
This week's question:
Imagine a simplified version of the game Battleship played on a 2D grid. The grid represents the sea, and each cell can either be empty (.) or contain a part of a ship (X). Ships are placed horizontally or vertically, and there are no adjacent ships. Given a grid, count the number of battleships in it. Extra credit: can you make a layout generator for the game given these rules?
Example:
const ships = [
['X', 'X', '.', 'X'],
['.', '.', '.', 'X'],
['.', '.', '.', 'X'],
['.', '.', '.', '.'],
];
numberOfShips(ships)
> 2
(you can submit your answers by replying to this email with a link to your solution, or share on Bluesky, Twitter, LinkedIn, or Mastodon)
How to poop outdoors in a way that won’t harm the environment and other hikers
Athena 1800 with GMK Hooty
Reuben Wu draws aerial geometries with drones and lasers across remote landscapes
Taco Bell rethinks AI drive-through after man orders 18,000 waters
It's amazing how much a colon can change a sentence!
For example:
Jane ate her friend's sandwich.
vs.
Jane ate her friend's colon.
That's all for now, folks! Have a great week. Be safe, make good choices, and make your community a little better!
Special thanks to Ezell, Ben, Kinetic Labs, and Marta for supporting my Patreon and this newsletter!
cassidoo
website | blog | github | bluesky | twitter | patreon | twitch | codepen | mastodon
2025-08-25 13:58:38
Hey friends!
I hope you had a good week! Mine was full of cleaning and getting excited for fall weather in Chicago. Onwards!
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Introduction to AT Protocol
MCSS: A modern classless CSS framework
ts-http-status-codes: A better way to manage HTTP status codes
Circular gallery of rounded images
I wrote about how I built my cry-tracking app, Ductts this week! I feel like besides that and swiffering my floors, I haven't gotten a lot done lately. My new baby is turning four months old (!) today, and between him and my toddler, we're just constantly chasing, feeding, changing, reading to, and playing with them. It's fun, it's good, and I'm grateful for maternity leave, but... I'm so exhausted all the time. I know it'll get easier eventually, so I'm staying as positive as possible and trying to savor the small moments (...and crying about them and logging into Ductts very often). Parenting is the most challenging joy, ever.
No sponsor this week! Please consider checking out one of the apps I've made recently:
Or, if you feel so inclined to help support my work financially in other ways, you can use Patreon or GitHub Sponsors (both of which get you access to a very fun Discord group)!
Last week, I had you make a laundry generator function. Squeaky clean good job Paul, Ten, Ender, Ida, Collin, Miguel, Elke, Jonathan, Kriszti, Dani, Vasanth, Andrew, Pedro, Victor, Christian, Stephen, Laasya, Amine, and Jeremias!
This week's question:
Given an array of order objects for a restaurant, each with a table number and a list of ordered items, write a function that returns an object mapping each table number to a summary of how many times each item was ordered at that table. Extra credit: Could you go so far as to make this a restaurant management game?
Example:
const orders = [
{ table: 1, items: ["burger", "fries"] },
{ table: 2, items: ["burger", "burger", "fries"] },
{ table: 1, items: ["salad"] },
{ table: 2, items: ["fries"] }
];
> orderSummary(orders)
{
1: { burger: 1, fries: 1, salad: 1 },
2: { burger: 2, fries: 2 }
}
// or, string output format:
"Table 1 ordered 1 burger, 1 fries, and 1 salad. Table 2 ordered 2 burgers and 2 fries."
(you can submit your answers by replying to this email with a link to your solution, or share on Bluesky, Twitter, LinkedIn, or Mastodon)
Landlines are making a comeback… with children
The Food Timeline
How we built Bluey’s world: tales from original series art director, Catriona Drummond
Which Keyboard size is right for you? (video)
Walking into solid objects can be painful, according to a recent pole!
That's all for now, folks! Have a great week. Be safe, make good choices, and call your parents!
Special thanks to Ezell, Ben, Kinetic Labs, and Marta for supporting my Patreon and this newsletter!
cassidoo
website | blog | github | bluesky | twitter | patreon | twitch | codepen | mastodon
