JavaScript Tutorials

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    Array.prototype.at

    Working with arrays is an essential skill in any programming language, especially JavaScript, as we continue to rely on external data APIs. JavaScript has added methods like find and `findIndex recently, but one syntax I love from languages like Python is retrieving values by negative indexes.When...

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    Command Line trash

    One of the first commands you learn when experimenting with command line is rm, the utility for deleting files and directories. Deletion is a core computer UI operation but operating systems use a "Trash" paradigm, where files are stored before truly deleted. With the...

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    How to Create a UUID in JavaScript

    The UUID identifier has been used in programming since the days a baby-faced David Walsh became a professional software engineer. My first exposure to UUIDs was via a ColdFusion app I inherited and ... the less we say about that the better. In any...

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    AggregateError

    One of the big themes of the web these days is concurrency, which leads to accomplishing tasks asynchronously. In doing so, the possibility of multiple errors can occur. Instead of providing a generic error, optimally you'd provide a wealth of error information. TheAggregateError...

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    jq for JSON

    I old enough to remember when we thought XML was going to change the programming world...then JSON saved us from that hell. Parsing and querying JSON data is fundamental task we've all coded for, but sometimes I just want to get some data locally with minimal...

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    React usePrevious Hook

    Hooks are essential for the functional component pattern in React. One frequent logic comparison with class components was comparing a previous prop value with a current prop value via lifecycle methods. So what's an easy pattern for duplicating previous value comparisons in functional components?The useRef and...

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    onInput Event

    Coding HTML forms has been painful my entire career. Form controls look different between operating systems and browsers, coding client side and server side validation is a nightmare, and inevitably you forget something somewhere along the line. Some behaviors don't act the way you'd...

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    Fix Seeing “0” in Your JSX Code

    The early days of the web felt like the wild west when it came to coding practices -- just make it work. Then we became enlightened to better practices, separating HTML from CSS and JavaScript. Then came React and JSX, where we combine JavaScript, HTML...

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    JavaScript Numeric Separators

    Writing good code is important -- writing code that's easily human readable is a next level skill. It's not often that APIs are introduced whose seemingly only useful function is making code more readable, but let me introduce you to JavaScript numeric separators: an API that...

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    Regular Expression Match Groups

    Regular expressions are incredibly powerful but can be difficult to maintain. They're a skill you learn on the job and, when the suits walk by, make you look incredibly smart if you have a few up on your screen. How can we solve the...