JavaScript Tutorials

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    Detect Cryptocurrency by Wallet Address

    I’ve always been a massive advocate of cryptocurrency. I love the technology, the ease of use, and the freedom that cryptocurrencies bring to the world. Despite my love of crypto, I know that adoption will take a long time and that the state of crypto...

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    Set Video Playback Speed with JavaScript

    I love that media has moved from custom plugins (Flash…gross) to basic HTML <video> and <audio> elements. Treating these media sources as just another element allows us to use CSS filters to adjust display, for example. The less we need to do with...

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    How to Debug Remote Browsers

    It's super frustrating when bugs pop up only in a remote browser. Something about that user, that device, or that environment is different, but I don't know what! And of course, I can't recreate it on my local development machine. The team at TrackJS...

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    How to Detect Text in Images

    Images are a great way to communicate without text but oftentimes images are used/abused to spread text within social media and advertisements. Text in images also presents an accessibility issue. The truth is that it's important, for any number of reasons, to be able to detect...

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    Detect if Element is a Web Component

    I've advocated for web components since before they became a spec, mostly inspired by the Dojo Toolkit's dijit framework. Empowering first class JavaScript widgets, as opposed to a mess of DIVs and templates, always made the most sense. Now that web components exist, and awesome...

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    IP Geolocation API

    Detecting geolocation information from your user provides you a massive advantage: improved conversion, better segmenting and analytics, and providing more relevant content. There are numerous paid services which will provide geolocation info but they're oftentimes too costly or short of valuable information. I was super impressed...

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    Resize Observer

    Creating websites that are reactive and responsive used to be considered advanced but responsiveness is a necessity for successful websites and apps. We've added media queries, matchMedia, and a host of other APIs to help developers make responsiveness easier and now we get a new...

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    Recursive Array.flat

    There was much talk about Array.prototype.flat during its early stages, starting with the name alone. Many developers preferred the name flatten but the spec differed from MooTools' implementation. MooTools would recursively flatten an array but the new, official flat implementation defaults one level of flattening,.The current...

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    Using Array reduce

    Every developer who specializes in any programming language will tell you there's a powerful tool the language provides that they rarely use and wish they knew more about. For me, it's Array.prototype.reduce. I quite enjoy the other Array methods like map, filter, and find...

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    Type Conversion with JavaScript Arrays

    JavaScript's loose nature allows developers to employ amazing tricks to do just about anything you'd like. I've detailed how you can filter falsy values in arrays using a filter(Boolean) trick, but reader David Hibshman shared another trick for typecasting array values the same...