JavaScript Tutorials

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    Fix Flow Node Issue “property querySelector of unknown”

    Flow, the static type checker used in many React projects, feels like a gift and a curse at times; a gift in that it identifies weaknesses in your code, and a curse that sometimes you feel like you're needlessly adjusting your code to satisfy Flow. ...

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    Convert HTML to Markdown

    One of my biggest mistakes with this blog was not finding a WordPress plugin that would allow me to write my posts with markdown; to this day I still need to write posts in "Visual" mode and then manually convert the post to HTML for "Text"...

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    console.timeLog

    I work on a really complex debugger at Mozilla but, and don't tell my colleagues, I sometimes enjoy simply using console.log and other console commands to get some simple output.  I know, I know, but hey -- whatever gets the job done.  A few years ago I...

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    Detect WebVR Support with JavaScript

    It's been two years since I was heavily involved with WebVR at Mozilla but, despite not contributing every day, I can see VR making leaps and bounds, from Firefox making an increased effort to Chrome pushing VR and Oculus and HTC (Vive) improving their offerings.  Native...

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    Get React Component Data by DOM Node

    Retrieving a React component's DOM node is fairly simple from within the component itself, but what if you want to work backward:  retrieve a component's instance by DOM node?  This is a task that the old Dojo Toolkit's Dijit framework allowed with the dijit.byId method, so...

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    How to Get a React Component’s Element

    JSX is an amazing pseudo-language for React, and if I'm honest, it's what brought me to love React so much.  Using React without JSX is cumbersome and frustrating, while using JSX is such an easier way to express your code.  One drawback of JSX, however, is...

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    React and autofocus

    While I love ReactJS, I can say that I sometimes find interactions that were easy during the pre-ReactJS are annoyingly difficult or at least "indirect".  One example is properly ensuring that a given <input> element gets focused when a button in a different component is clicked; in...

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    The Dark Side of Promises

    Since the release of es6 many new features have found their way into NodeJS, but non had quite the same impact as promises. Promises have been developed for the browser before es6 was even a thing. There were several implementations that have been used like jQuery's...

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    Destructuring and Function Arguments

    The JavaScript language has benefitted from some really awesome new features over the past few years, including arrow functions, the spread operator, and default function argument values.  Even if your browser doesn't yet support proposed JavaScript API syntax additions, you can use a tool like...

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    5 Crucial Concepts for Learning d3.js and How to Understand Them

    You may have already heard about d3.js, the dazzling JavaScript library that lets you create beautiful charts and graphics with just a few lines of code. You might have seen some of the fantastic examples of D3 in action, or you may have heard that...