The .classList() API
Assuming you have an element in the DOM: <div id="el"></div> Get a reference to that DOM element: const el = document.querySelector("#el"); Then you can manipulate the classes on that...
View ArticleInject HTML From a String of HTML
Say you have some HTML that is a string: let string_of_html = ` <div>Cool</div> `; Maybe it comes from an API or you've constructed it yourself from template literals or something. You can...
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Getting First and Last Items in Array (and splitting all the rest)
I needed to get the first item from an array lately in JavaScript. Hmmmm … lemme think here. I remember that .pop() is for snagging the last item from the array, like this: const arr = ["This",...
View ArticleRequired Parameters for Functions in JavaScript
Ooo this is clever! I'm snagging this from David's blog. const isRequired = () => { throw new Error('param is required'); }; const hello = (name = isRequired()) => { console.log(`hello ${name}`)...
View ArticleRemove Duplicates from an Array
Compiled by Svein Petter Gjøby: const array = [1, 1, 1, 3, 3, 2, 2]; // Method 1: Using a Set const unique = [...new Set(array)]; // Method 2: Array.prototype.reduce const unique =...
View ArticleAlphabetizing Arrays, Objects, and Arrays of Objects
An array: let fruits = [`bananas`, `Apples`, `Oranges`]; You can sort of alphabetize that as easy as: fruits.sort(); But notice the inconsistent casing in the array... uppercase characters will all be...
View ArticleAdd a Number to Two Variables At Once
You can initialize two variables to the same value at once, kinda: var foo, bar; foo = bar = 10; But there is no similarly easy mechanism to add, say, 5 to both foo and bar at the same time. Of course,...
View ArticleReplacements for setInterval Using requestAnimationFrame
When it comes to animation, we're told that setInterval is a bad idea. Because, for example, the loop will run regardless of anything else going on, rather than politely yielding like...
View ArticleSelect Random Item from an Array
var myArray = [ "Apples", "Bananas", "Pears" ]; var randomItem = myArray[Math.floor(Math.random()*myArray.length)]; (more…)
View ArticleConvert Polygon to Path Data
I've had to do this a few times recently so I thought I'd save the method. StackOverflow has a method that works great: [].forEach.call(polys,convertPolyToPath); function convertPolyToPath(poly){ var...
View ArticleAlphabetizing Arrays, Objects, and Arrays of Objects
An array: let fruits = [`bananas`, `Apples`, `Oranges`]; You can sort of alphabetize that as easy as: fruits.sort(); But notice the inconsistent casing in the array... uppercase characters will all be...
View ArticleAdd a Number to Two Variables At Once
You can initialize two variables to the same value at once, kinda: var foo, bar; foo = bar = 10; But there is no similarly easy mechanism to add, say, 5 to both foo and bar at the same time. Of course,...
View ArticleReplacements for setInterval Using requestAnimationFrame
When it comes to animation, we're told that setInterval is a bad idea. Because, for example, the loop will run regardless of anything else going on, rather than politely yielding like...
View ArticleSelect Random Item from an Array
var myArray = [ "Apples", "Bananas", "Pears" ]; var randomItem = myArray[Math.floor(Math.random()*myArray.length)]; (more…)
View ArticleConvert Polygon to Path Data
I've had to do this a few times recently so I thought I'd save the method. StackOverflow has a method that works great: [].forEach.call(polys,convertPolyToPath); function convertPolyToPath(poly){ var...
View ArticleCross-Browser Dependency-Free DOM Ready
Denis Ciccale's version: var DOMReady = function(a, b, c) { b = document c = 'addEventListener' b[c] ? b[c]('DocumentContentLoaded', a) : window.attachEvent('onload', a) } DOMReady(function () {...
View ArticleRemove an Element
For whatever reason, an element can't destroy itself in JavaScript. jQuery has a method for this, which is nice because this is how we think: $(".remove-me").remove(); But there is no direct equivalent...
View ArticleLoop Over querySelectorAll Matches
You can loop over Arrays really easily in JavaScript with forEach, but unfortunately it's not that simple with the results of a querySelectorAll. /* Will Not Work */...
View ArticlePrint Object To Screen
PHP has a nice print_r function for printing out information about a variable to the screen. console.log() is great for that in JavaScript also, but sometimes you just need/want to look at it on the...
View ArticleCheck if font-family is Honored
function checkFont(strFamily) { var objDiv = document.createElement('div'); objDiv.style.fontFamily = strFamily; objDiv.appendChild(document.createTextNode('FONT TEST')); if (window.getComputedStyle) {...
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