Why compose() is right-to-left
Published on in JavaScript
Functions composed together with compose()
are called from right to left.
It feels unintuitive at first,
but it's conventional
and kind of makes sense.
JavaScript
Why
React's ecosystem is a dumb necessity
Published on in JavaScript, Mithril.js, Rant and React
Last updated on
React's ecosystem is large, which is a good thing: lot's of great libraries to use. But it's also a bad thing: most of those libraries are compatible only with React.
JSX vs HTM (Hyperscript Tagged Markup)
Published on in JavaScript and React
HTM provides a transpiler-free alternative to JSX via tagged templates. HTM has some limitations, but can be used in browsers and can be good for smaller projects.
FizzBuzz in JavaScript with infinite arrays and multimapping
Published on in JavaScript
Fun way to solve the simple puzzle.
Infinitely repeating arrays
and mapping over multiple arrays
almost makes the remainder/modulo operator (%) unnecessary.
Memoized Fibonacci function in 1 line of JavaScript
Published on in JavaScript and TypeScript
Or 2 lines for better readability.
Using recursion,
||= (logical OR assignment operator)
and more!
How to render Optimizely Content Recommendations using React
Published on in Episerver, JavaScript and React
Last updated on
Also known as Episerver/Idio Content Recommendations. The usual way of using a Mustache template can be circumvented by using a JavaScript proxy.
How to get component's HTML without mounting in Mithril.js
Published on in JavaScript and Mithril.js
Last updated on
Create a DocumentFragment
and render the component to it.
Then there's no need to mount the component to the DOM.
How to debounce events in Mithril.js
Published on in JavaScript and Mithril.js
Last updated on
Disable auto-redraw with event.redraw = false
and use a timeout.
How to nest selectors in Mithril.js for extra brevity
Published on in JavaScript and Mithril.js
Last updated on
m.nest('ul > li', 'Item')
can be achieved with reduceRight().
How to pretty print JSON in JavaScript
Published on in JavaScript
Last updated on
Run JSON.stringify(object, null, 2).
Adjust the number for a different level of indentation.
3 ways to convert a path into cumulative segments in JavaScript
Published on in JavaScript and Regular expressions
Last updated on
How to convert
'/foo/bar/baz/'
into an array of
'/', '/foo/', '/foo/bar/', and '/foo/bar/baz/'.
Example use case: building breadcrumb navigations.
JavaScript's Date() constructor is bad at parsing dates
Published on in JavaScript
Last updated on
And Date.parse() too.
They are strongly discouraged
due to browser differences and inconsistencies.
Use only proper date time formats
or use a library for parsing fancy formats.
"Illegal invocation" errors in JavaScript
Published on in JavaScript
Last updated on
JavaScript throws an "Illegal invocation" error
when the context of a function is lost,
i.e. when the function's this keyword isn't referring to where it should.
Mnemonic for array.shift() vs array.unshift() in JavaScript
Published on in JavaScript and Mnemonics
Last updated on
shift() removes the first array item,
and unshift() prepends items to the array.
But how to remember which is which?
Using non-default locales with toLocaleString() in Node.js
Published on in JavaScript, Node.js and npm
Last updated on
With Node.js 13+,
it should just work.
With earlier Node.js versions,
you need to install and use the full-icu package.
Calculating week numbers in JS is surprisingly complex
Published on in JavaScript
JavaScript doesn't provide a native way to get the week number of a date. Just use a library instead.
How to do overlapping matches with regular expressions
Published on in JavaScript and Regular expressions
E.g. how to capture overlapping pairs of letters from the string 'abcde',
i.e. 'ab', 'bc', 'cd' and 'de'.
Spoiler: with lookahead and lookbehind assertions.
fn.apply() vs fn.call() in JavaScript + better alternative
Published on in JavaScript and Mnemonics
Last updated on
Mnemonic:
"a" (apply()) for an array,
"c" (call()) for commas.
But Reflect.apply() is better.
Uncontrolled form inputs in React
Published on in JavaScript and React
Last updated on
If you need form input values only at the time of form submission, uncontrolled inputs can be nice to work with.
Notes on Tail Call Optimization: The Musical!
Published on in JavaScript
Last updated on
My quick notes on a funny but informative video (11:27) that explains how tail call optimization (TCO) works. Bonus: does JS support TCO? Spoiler: yes but no.
How to chunk an array in JavaScript
Published on in JavaScript
Last updated on
A simple reducer to chunk (split) an array into smaller arrays.
How to bypass Episerver's Content Delivery API when doing Ajax requests
Published on in C#, Episerver and JavaScript
Requests with the Accept header set to application/json
are automatically routed to Content Delivery API.
Here's how to bypass it
and make the request go to a page controller instead.
Hyperscript: hyperior alternative to JSX
Published on in JavaScript, Mithril.js and React
Last updated on
JSX is just JS under the hood.
Hyperscript is like that JS,
but better.
Example:
h('a.link', { href }, 'Click me')
is nicer than
<a className="link" href={href}>Click me</a>,
right? Right?!