Moddable was honored to exhibit at FOSDEM 2023 in Brussels, Belgium. FOSDEM is the preeminent open source software event in Europe. We were very fortunate to have a stand dedicated to open source Embedded JavaScript because lingering pandemic concerns limited the number of exhibitors. Our stand was in the IoT area, which was busy throughout… Read More


The end of the year is an opportunity to look back at the amazing progress Moddable has made in our mission to bring the power of the JavaScript ecosystem to embedded developers. The Moddable SDK continues to grow in both breadth and depth to support new devices, new capabilities, and familiar APIs, giving developers an… Read More


All year the team at Moddable works with our clients and community of developers to bring the power of the JavaScript ecosystem to embedded developers. The end of the year at Moddable is an opportunity for us to build a project using the technology we’ve been building all year. This year’s project weaves Neopixels into… Read More


Everyone involved in delivering software for resource-constrained hardware knows that performance is a key challenge. Low-cost hardware has just enough performance to make a great product possible, but only if the software is careful not to overwhelm the hardware. It is easy to notice that a product is performing slowly. What’s difficult is figuring out… Read More


Maintaining a reliable network connection to the internet is fundamental to IoT products. Unfortunately, network connections aren’t reliable: they can fail in many ways. Products must be engineered to operate reliably on unreliable infrastructure. Many products use Wi-Fi to connect to the internet and Moddable has worked with many clients to successfully deliver products that… Read More


Comparing and copying JavaScript objects are fundamental operations that are remarkably complex to implement correctly and efficiently. Because these operations are not built into the JavaScript language, various solutions have arisen to make life easier for developers. Web browsers provide the structuredClone function to make a deep copy of an object. Node.js provides deepEqual assertions… Read More


Introduction Microcontrollers don’t usually have a built-in file system. Projects that need a file system have a choice of which file system to use. Popular choices include the FAT file system and SPIFFS, and the Moddable SDK supports both. These file systems work well, but have limitations that make them difficult for developers to work… Read More


Making sure that the Moddable SDK and the XS JavaScript engine run correctly and reliably is a big project. There are hundreds of features and APIs that must be verified on a wide variety of devices. Testing on devices is particularly challenging, as many don’t even have enough storage space to hold the test suite.… Read More


Delivering a modern user experience on low-cost embedded hardware has been a key focus of the Moddable SDK from the start. The Moddable SDK is regularly updated with new rendering capabilities to expand the kinds of user experiences that can be created. Last year support for animated GIFs arrived and earlier this year it got… Read More


The fonts displayed on the screen of an IoT product are a key part of its brand, establishing the overall feel of the product. All of Moddable’s commercial clients use the custom font support in the Moddable SDK to brand their products. While it has always been possible to incorporate custom fonts into products, it… Read More


One of the defining features of the Moddable SDK is its outstanding support for displays in IoT products. Much of that work has focused on LCD touch screens, but ePaper displays have also been supported from the beginning. Recent work has brought broader and deeper support for ePaper displays, making the Moddable SDK the best… Read More


Today Moddable is launching a public effort to bring the Moddable SDK to the Raspberry Pi Pico development board. The Moddable SDK includes XS, the only modern JavaScript engine designed for resource constrained microcontrollers. The Pico is powered by the new RP2040 microcontroller (MCU) from the same organization that created the Raspberry Pi family of… Read More


Moddable believes JavaScript is the best language for building IoT products. We’ve heard from many developers that they agree with us, but that it is important to them to be able to use TypeScript. If you aren’t familiar with TypeScript, it is a language created by Microsoft that adds features to JavaScript focused on type… Read More


The XS JavaScript engine brings the many benefits of modern JavaScript to embedded systems like those that power IoT products. The latest release of XS is a major step forward. It delivers new language features, performance optimizations, improved conformance with the ECMAScript specification, and updated support for the Secure ECMAScript proposal. This blog post summarizes… Read More


The latest update to the XS JavaScript engine continues to focus on adapting and optimizing JavaScript for embedded systems. In this release, the majority of these improvements take place during the preload phase, part of the build process. Additionally, this release adds support for top-level await and WeakRef, two new JavaScript features expected to be… Read More


This blog post is about performance improvements in the way the Moddable SDK reads SPI flash. That might not sound exciting, but the result is: our favorite rendering benchmark (balls) runs 50% faster. When you update to the latest Moddable SDK, you’ll get those changes automatically. The details behind the improvements are an interesting window… Read More


Firmata is a popular protocol for controlling remote hardware resources. It is often used to allow a more powerful device running a non-real time operating system, such as Linux, to control the hardware ports of a less powerful microcontroller device with a real-time operating system (or no operating system at all). The most common use… Read More


The latest release of our XS JavaScript engine puts in place fundamental new capabilities to advance Moddable’s mission of safely opening IoT products to third party software. These new capabilities are implementations of proposals on track for standardization in Ecma TC39, the JavaScript language committee. The two most significant developments are described in the “Truly… Read More


At Moddable, we believe individuals should have control of the software in the products they own. Some people will use that control to write their own software, while others will use that control to choose the software that delivers the behaviors and privacy they design. Moddable’s extensive work in JavaScript contributes to that goal by… Read More


The Moddable SDK now supports rotating the image shown on displays using features built into some display controllers. This allows the display to be rotated to 0, 90, 180, and 270 degrees at any time with no added overhead. Build-time Rotation with Software The Moddable SDK has always included support for drawing to displays at… Read More


The latest push of the XS JavaScript engine implements support for the forthcoming ECMAScript 2019 standard. The ECMAScript 2019 standard includes several new capabilities and refinements but no major new features. A complete summary of the changes with links to details is available on the “2ality – JavaScript and more” blog by Axel Rauschmayer. For… Read More


The JavaScript language is preparing to add built-in support for integers of arbitrary size with a new feature named BigInt. The built-in Number type is accurate to 53-bits of precision, which is insufficient for many tasks. By standardizing BigInt into the language, developers benefit from having a single API available in all environments and JavaScript… Read More


Sometimes a display is just a display. You don’t need an interactive user interface, you just need to show an image. Using the Moddable SDK, this is easy to do by building a small application to draw the image. There are examples to display a PNG, an animated GIF, and to stream JPEG images from… Read More


There’s been a lot of good work in the Moddable SDK in recent months. This blog post highlights a some of the recent additions and improvements. mDNS The mDNS protocol is arguably the most robust solution available for IoT devices connected to the same local network to discover one another. It is a mature technology… Read More


NeoPixels are strings of bright LEDs that have been popular within the maker community for adding animated illumination to objects. Several recent ESP32 based development boards have built-in NeoPixels, including the … Read More


We’ve recently enabled the JavaScript eval function on embedded devices using the XS JavaScript engine. Our long-held position is unchanged: it is almost always a bad idea to compile JavaScript on an embedded device. The reasons that eval are used on the web, for example, do not typically apply to embedded development. Still, compiling scripts… Read More


In recent months, Moddable has received inquiries for the ability to render a QR Code in the Moddable SDK. This article describes the module we created to support QR Code rendering, together with some of the design and implementation choices we made along the way to provide efficient and flexible QR Code support. What’s a… Read More


In May of 2017, Moddable Tech presented our XS JavaScript engine to at the Ecma TC-39 meeting at Google New York. We were graciously invited by Brendan Eich, the creator of JavaScript, to share our work applying JavaScript to extremely resource constrained embedded hardware. Brendan believed it would be valuable for the committee to see… Read More


Moddable is working hard to make it much easier to add displays to consumer electronics products. A display shows more information quickly and concisely than a few blinking lights or a voice interface. But, it is challenging today to build a product with a display at a reasonable cost with a modern user interface. One… Read More


The most recent push to the Moddable repository on GitHub is a big one. It includes the following:

  • New regular expression engine — A completely new regular expression engine written from scratch for use by XS, Moddable’s JavaScript engine. It is almost 10x smaller than its predecessor with more features and improved conformance. We believe…

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Introduction The JavaScript language includes support for regular expressions, a compact and powerful tool to perform search and replace operations on strings. Regular expressions can be considered a separate language within JavaScript, with its own syntax and behaviors. Just as implementing a JavaScript engine is a major undertaking, properly implementing a new regular expression engine… Read More