Why they switched, how they migratedāand why they wouldnāt do it today
In early 2018, The Guardian, a British newspaper and online publication, switched its 2.3m content items from MongoDB to PostgreSQL.
Why did they switch? What would they do differently today?
The Day the London Servers Baked
In July 2015, a massive heatwave struck London, with the unusual consequence of The Guardian switching from MongoDB to PostgreSQL just three years later.
At the time, The Guardianās data was in a standard NoSQL database; MongoDB stored locally at Guardian Cloud, the data center in the basement of The Guardianās office near Kings Cross.
While writers for The Guardian were live-blogging about the heat, developers at The Guardianā¦
Hey Rizky, did you ever get it working right for keen-slider? It's giving me problems
WEB PERFORMANCE
Googleās about to penalize slow websites. If you care about search engine optimization (SEO) and your ranking on Google, you should pay attention to this change in their search algorithm
I was cussing on the toilet, again, because Iād accidentally clicked a link on my phone while reading The Ringerās NBA coverage.
My mom would be embarrassed, Iām sure.
You see, I prefer to open links from their website in a new tab, because I donāt want to hit the Back button. Why would such a minor thing cause me to start cussing in such a compromising position?
Itās because their website is slow. If I hit the Back button, I have to wait for their site to load again, and it almost always loses my place as dozens ofā¦
How I went from physical therapist to SEO & website performance expert.
My Journey from Physical Therapy to Tech
You may be curious as to why a physical therapist, massage therapist, and strength coach is also an SEO & web performance expert.
Having spent the last decade in sports medicine, including several years as a full-time physical therapist (and Airbnb SuperHost who got over 500 reviews in 3 years), it was time for a change ā so I started blogging on Medium to refresh my web development skills.
You see, I started building websites professionally back in 2001, and I even built a PHP app for LiveJournal that earned a few hundred dollars in advertising income. ā¦
WEB PERFORMANCE
Either method can work. Array.prototype.filter() is infinitely more powerful than Array.prototype.includes(), while the .includes() method is easier to read and offers much better performance.
If you need to know if a JavaScript array contains an item, you have a couple of options other than just writing a for loop.
The most obvious alternative is Array.prototype.includes(), but using Array.prototype.filter() might save you future refactoring.
āThe
includes()method determines whether an array includes a certain value among its entries, returningtrueorfalseas appropriate.ā
ā MDN Docs
If you need to return the first matching item, youād use Array.prototype.find() instead of .includes().
The more powerful .filter() method lets you test the entire array with an arbitrary criteria, and it returns a new array of allā¦
Medium members can now access a lot more content about software engineering than ever before, thanks to The Pragmatic Programmers in a partnership with Better Programming.
The Pragmatic Programmers put their entire collection of textbooks about software development and web development on Medium this week.
Is this a good thing or a bad thing for web developers?
My favorite titles from the list:
- Your Code as a Crime Scene
- Mazes for Programmers
- Real-Time Phoenix
- Real-World Kanban
- React for Real
I counted 142 books in the collection. Thatās a ton of content.
As I commented on HackerNews, I think this is a great opportunity for programmers to be able to find a lot more answers through organic search.
Previously youād have to know that the topic wasā¦
If you need all array items converted into a single string without commas separating the elements, then you need to pass the empty string "" as an argument to the array .join() method.
Turn an Array into a String Without Commas
When you call JavaScriptās .join() (Array.prototype.join()) method with no argument, youāre actually using a comma.
The default behavior of .join() is to convert an array to a string with commas, so itās the same as calling .join(",") explicitly.
When you call .join(",") you specify that you want a string literal "," to be the separator character, which will occur between each element. But itās the same as .join() with no argument at all.
If you call .join("") with the empty string "" instead, then all of the elements will be joined together without commas.
Would you pay for the new Stackbit service? Do you like to use themes from sites like Jamstack Themes in your projects, or do you always start from scratch? Is it better to always build your own design library? When is paying for convenience worth it?
Stackbit just released their pricing plans for their Jamstack āinstant siteā service, which I love and have written about before:
My initial impression is that thereās a lot of value for anyone making websites in a small team. Is it enough to make the $29 and $149 price points attractive for teams of 4 users and 10 users respectively?
Iāll still use Stackbitās free tier any time. I mean thereās literally a Create Site button on the excellent Jamstack Themes site:
ES6 introduced let and const as alternatives to var for declaring variables in JavaScript. Because const is not hoisted to the top of the execution context in the same way var is, const should be faster, right?
Execution context and hoisting
The first lecture in Tyler McGinnisās Advanced JavaScript course covers execution context and hoisting, and it got me wondering about instantiating variables using var and const in JavaScript.
After the lecture, I was left thinking that the JavaScript keyword var might be slower than the keyword const, because var needs to be hoisted.
Perhaps that extra step in the execution context hurts performance. If so, we would also expect to find that let is slower than var.
(If youāre not sure about the difference between each of these keywords for declaring variables, Iāve previously compared let, var, and const).
You can access object properties in JavaScript in one of two ways: . dot syntax or [] bracket notation. Hereās why there are two property accessors and what the difference is between them.
One of the first things JavaScript developers learn is that there is a difference between primitive types (like numbers and booleans) and objects (like arrays and Dates).
You typically recognize objects because they are invoked with the object literal syntax ({}, curly brackets) and then accessed using a single period character, the . dot syntax.
Calling the . dot syntax is what is called an object property accessor, as it allows you to access the specified property.
āProperty accessors provide access to an objectās properties by using the dot notation or the bracket notation.ā ā MDN Docs
Object properties areā¦
Dr. Derek Austin š„³
š¤ The physical therapist who writes JavaScript šŖ Web Developer š Mentor š§ DPT š SEO Expert š React š Jamstack š¬ Ask me anything š DoctorDerek.com š
