/* Code Comments */74 posts tagged with "javascript"
javascript: testing private methods
2022-11-28
|~3 min read
|487 words
Imagine the following scenario: you have a javascript module that’s relatively complicated. So complicated that you’ve broken it down into a…
javascript: making methods available for testing
2022-11-28
|~1 min read
|179 words
A fairly common experience in the Javascript world is that when you want to make a method available for testing, it needs to be exported…
javascript: combining regular expression patterns
2022-11-28
|~2 min read
|310 words
I was working on updating my blog and I wanted to have excerpts. Unfortunately, the excerpts were coming in with a lot of additional context…
node: async filtering
2022-11-28
|~5 min read
|966 words
Preamble I was recently working on porting my blog to Remix. As part of this, I needed to parse my markdown files that constitute all of the…
e notation
2022-11-28
|~1 min read
|109 words
I was working on a toy problem recently which involved something called a “Giga” second. This is 10^9 seconds. Easy enough, we can calculate…
higher order components in react
2022-11-28
|~2 min read
|347 words
Imagine you have a prop that you want to be passed all the way through to the DOM. If you try and pass through a prop that isn’t…
snowpack: experimenting with a new build tool
2022-11-28
|~7 min read
|1238 words
Snowpack is a new(er) addition to the build tools available on the front-end. I had the opportunity to start a new project recently and I…
react: scroll to the top of page on transition
2022-11-28
|~2 min read
|225 words
I’m currently working on a single page app with React that uses React Router. When navigating between “pages” (that is the URL changed and…
javascript: optional chaining
2022-11-28
|~3 min read
|476 words
One of my favorite recent additions to Javascript is Optional Chaining. This behavior, which allows a program to quickly ascertain whether a…
accessing media queries in javascript
2022-11-28
|~2 min read
|242 words
When we write media queries it’s mostly the case that we just need to reference that within our style sheet. What about those cases where we…
object.assign vs spread syntax
2022-11-28
|~5 min read
|958 words
I started programming after ES6 was released - which is to say, I missed a lot. One of those features I never really needed to understand…
styleguides
2022-11-28
|~1 min read
|184 words
Javascript is the wild west. There are no rules. Or that’s what they tell me at a minimum. A large percentage of this blog is dedicated to…
global themes with css variables
2022-11-28
|~1 min read
|63 words
Themes are hard. I wrote about them previously here Emotion and Styled-Components aim to address this problem with a theme provider that…
javascript generators for conditional lists
2022-11-28
|~4 min read
|619 words
Generators are a language feature that I don’t see used very commonly - at least in Javascript land (I remember going to a php user group…
javascript: image blob
2022-11-28
|~2 min read
|223 words
Recently I was working with an API that was returning binary data of images. I wanted to render them to a page which led me to discover the…
getters & setters
2022-11-28
|~1 min read
|84 words
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get the use of getters seems to be much more common within the…
regex: untracked capture groups
2022-11-28
|~3 min read
|405 words
When I write regular expressions, I often find myself grouping logic between parenthesis. The issue is that these groups are remembered and…
regex: javascript global flag
2022-11-28
|~2 min read
|235 words
Recently I wrote about my regular expression prowess with figuring out a pattern to match on markdown links. When I went to implement it…
regex: grouping matches
2022-11-28
|~2 min read
|313 words
As regular expressions get longer and more complicated capture groups can be nice to organize the different pieces of a match. For example…
regex: markdown links
2022-11-28
|~4 min read
|685 words
In the Markdown Spec there are several ways to write a link. The most common way I’ve seen / used is a pair of brackets followed by…
custom errors in javascript
2022-11-28
|~1 min read
|146 words
/*_ really just need to add some wrapping around this. the body’s there. _/ When handling errors, it’s sometimes convenient to handle based…
creating empty arrays and matrices in javascript
2022-11-28
|~3 min read
|516 words
Imagine we want to create an matrix with Javascript. Javascript provides a number of different options for this, but it’s one of those…
reasons to prefer maps over pojos* (i.e. objects)
2022-11-28
|~4 min read
|656 words
*Note: A POJO is actually a “Plain Old Java Object”, but I’m talking about Javascript, so it’ll be “Plain Old Javascript Object” today…
packing and unpacking tuples in python
2022-11-28
|~3 min read
|447 words
Unlike a list or a dictionary, in Python, tuples are immutable.1 This is clear when investigating the methods available on the object…
list comprehension in python (with comparisons in javascript)
2022-11-28
|~5 min read
|994 words
Python has a very concise syntax for creating new lists called List Comprehension. List comprehension is a way to define a new list based on…
truthy and falsey: javascript edition
2022-11-28
|~2 min read
|212 words
One of the most challenging things when getting started with Javascript is understanding comparisons. To do so requires understanding a few…
package comparison: bcrypt vs bcryptjs
2022-11-28
|~2 min read
|277 words
In learning more about password management and salting/hashing (which I wrote about here) - I found bcrypt (which I wrote about using here…
javascript pop up boxes
2022-11-28
|~2 min read
|320 words
For a while now I’ve known about Alerts. They’re the shouting from the rooftop equivalent of Javascript. Instead of simply logging some…
finding groups - combinatorics with javascript
2022-11-28
|~5 min read
|926 words
Imagine you’re planning a dinner party. You have a table that can comfortably seat 6, but you have 20 friends. How many combinations can you…
implementing debounce and throttle with javascript
2022-11-28
|~11 min read
|2147 words
I’ve written about debouncing and throttling in the past in the context of scroll events, but I wanted to take a moment and implement them…
why sets are always unique: hashing
2022-11-28
|~2 min read
|286 words
I was doing a little reading on Sets this morning and had a bit of an ‘a ha’ moment about why Sets are always unique. Let’s say we have an…
styling markdown code snippets with prismjs
2022-11-28
|~7 min read
|1215 words
There are a number of different syntax highlighters for Javascript, but the one I’ve been using lately is PrismJS (due in large part to its…
object oriented javascript: extending classes
2022-11-28
|~6 min read
|1005 words
I’ve written in the past about OO in Javascript, but recently I was working on learning more about heaps and as I pulled together my own…
simple searching with html, css, and js
2022-11-28
|~2 min read
|289 words
As one of the fortunate few (relatively) who learned to make websites after the ascendency of React, I find that I often struggle when…
shared events between window, document, and htmlelements
2022-11-28
|~9 min read
|1783 words
When it comes to coding, there’s always something new to learn. One of the areas I find I have a hard time with are Take, for example, this…
form validation: preventdefault and onsubmit vs onclick
2022-11-28
|~4 min read
|780 words
A little over a year ago, I first discovered the power of and and wrote about it Better Form Submissions with Event.preventDefault and…
mocking async functions with waitfor
2022-11-28
|~3 min read
|480 words
Frequently, I find myself needing to mock out (or fake) an asynchronous call to test my API I’m developing. I hate having to remember the…
object oriented javascript: class instantiation patterns
2022-11-28
|~8 min read
|1468 words
Update: I wrote a follow up post on how to extend classes in Javascript. What are classes anyway? A class is an entity that is capable of…
transpile vs. compile
2022-11-28
|~1 min read
|167 words
What does it mean when we say that is a transpiler? According to Shawn Wang (known on the internet as swxy), when transpiles, it “compile…
global themes, variants, and modes with styled-components
2022-11-28
|~2 min read
|332 words
If I were to list my strengths, web design wouldn’t top the list. None the less, I like learning about it and know that I’ll continue to…
another angle to understand global state with react: next.js
2022-11-28
|~2 min read
|327 words
Recently, I was playing around with Next.js (simply referred to as Next from here on) to see how a framework might make building React…
easy logging with bunyan
2022-11-28
|~3 min read
|487 words
Another entry in my Package Discovery series. Today, I’m looking at logging with ! Two steps to easily generate more readable logs: Install…
mixing es modules and commonjs modules: don't
2022-11-28
|~3 min read
|539 words
Progress toward a unified module system in Javascript is proceeding, but we’ve yet to arrive at a unified experience. While we wait, I ran…
calculating the average of an array with reduce
2022-11-28
|~2 min read
|316 words
I had to find the average of a set with potentially undefined values. If a value was undefined, I wanted to skip it all together. For…
private fields and methods in javascript
2022-11-28
|~3 min read
|590 words
When I was first learning about Javascript (so, several months ago), I found this article from Douglas Crockford about private variables and…
finding the most recent date in an array, with conditions, using dayjs
2022-11-28
|~5 min read
|902 words
There are a lot of different ways to approach date math (I’ve written about some in the past), but recently, I had to find the best way to…
mock api call with promised settimeout
2022-11-28
|~1 min read
|116 words
I was recently working on a project where I wanted a loading state while an API resolved. Instead of testing with a live API, I wanted to be…
graphql fragments: reuse and variables
2022-11-28
|~5 min read
|812 words
After thinking more about Lee Byron’s talk and some of the uses for fragments1, I still had some questions. Specifically - how do you reuse…
chai testing - expect's optional parameter
2022-11-28
|~1 min read
|148 words
When testing with the Chai assertion library, I like the syntax and how it reads. The example from the docs demonstrates this nicely…
common date math in javascript
2022-11-28
|~3 min read
|504 words
I’m a big fan of libraries like Moment and DayJS. They make dealing dates in Javascript so much easier. Sometimes though, you just need to…
converting synchronous code to asynchronous
2022-11-28
|~5 min read
|819 words
I often find myself looking up patterns for converting synchronous code into async variants in Javascript. Whether it’s remembering how…
initializing a class
2022-11-28
|~2 min read
|246 words
Continuing the trend of learning more about Javascript classes of late, I found the following recently and thought it was quite interesting…
javascript: aha moments with classes - part deux
2022-11-28
|~3 min read
|467 words
Recently I wrote about my aha realization of what exactly we’re doing when we pass the props that a class constructor receives to super. In…
javascript: aha moments with classes
2022-11-28
|~4 min read
|706 words
When we define a class component as a derivation of a base class, this gives us access to all of the base class’s public (and protected…
creating a downloadable file
2022-11-28
|~2 min read
|367 words
I thought this was pretty cool. Imagine you want to create a file programmatically and allow a user to download it. For the sake of this…
property accessors and typescript
2022-11-28
|~1 min read
|198 words
Came across an interesting example of a rarely used feature (at least for me) in Javascript creating unexpected results with Typescript…
creating subsets: object.entries, object.fromentries, and sets
2022-11-28
|~4 min read
|726 words
universe of options I want to highlight one way to create a subset of data. To get us started, let’s think about a universe of data. It’s a…
stringifying sets
2022-11-28
|~1 min read
|91 words
In Javascript, Sets are Objects with a few special attributes. Notably, they’re iterable collections of unique elements. One of the…
creating objects
2022-11-28
|~3 min read
|440 words
The other day I came across a pattern for creating objects I couldn’t quite understand. The code looked a little like this: My confusion was…
exporting a named function as default
2022-11-28
|~1 min read
|198 words
Back in February I wrote a primer on exports and require. While the primer was helpful, one piece that never quite clicked, was how to…
supporting submit on enter
2022-11-28
|~3 min read
|539 words
When asking users for their input, it’s often a pleasant user experience to allow them to submit the form by pressing “Enter”. In fact, that…
bubbling up exceptions and throwing objects
2022-11-28
|~3 min read
|533 words
Every time I’ve thrown an error, I’ve used the object. It turns out, however, you can throw anything. I probably knew this intuitively, but…
swapping array elements in place, destructuring, and automatic semicolon insertion
2022-11-28
|~2 min read
|265 words
About a year ago, I learned about bitwise operators and using them to swap elements of a list in place. With Array Destructuring, Javascript…
regex in javascript strings: remove numeric or alphabetic characters
2022-11-28
|~1 min read
|103 words
Built into Javascript’s primitive are Regex methods such as and .1 We can use the latter to sanitize inputs. A simply way to clean a phone…
what is `require.resolve` and how does it work?
2022-11-28
|~2 min read
|374 words
In order to understand , part of the Node API, we must first understand its context. Namely, the module and how it fits within the realm of…
storybook.js and static image files
2022-11-28
|~2 min read
|308 words
Storybook supports static files, like images. But it wasn’t working for me. In fact, the way to make a story with a static file is really…
simple way to swap variables using javascript
2022-11-28
|~3 min read
|430 words
I’ve been learning about some of the ways you can use destructuring to make my Javascript more declarative and communicate my intent more…
currying - an introduction with function declarations & expressions
2022-11-28
|~4 min read
|766 words
For a long time, I hated seeing functions like this: . I thought this was just “code golf” (the idea of reducing a function to its shortest…
closure & lexical scope
2022-11-28
|~3 min read
|450 words
When we say that Javascript is lexically scoped, what we mean is that a function will have access to the variables in the context in which…
rename variable while destructuring in javascript
2022-11-28
|~2 min read
|205 words
I recently came across a situation where I had two different props in a component that had the same name (they were in different parts of…
lessons in queryselector and the importance of understanding mechanism
2022-11-28
|~3 min read
|460 words
NB: The below illustrations are inspired / adapted from MDN’s great page on QuerySelector. I did not come up with these examples (though I…
custom sort functions with javascript
2022-11-28
|~4 min read
|613 words
Javascript’s built-in sort is powerful and fast. However, there are many times when you will want to sort in a custom fashion. Whenever I…
adding indexes to mongo + a case study
2022-11-28
|~4 min read
|702 words
I’ve been working on projects with larger data sets recently and have begun to notice that not all queries resolve in one or two…
axios and routing with baseurls
2022-11-28
|~2 min read
|382 words
I was unifying multiple micro services into a single front-end. To do this efficiently, I wanted to create a single proxy that sat in front…