Firefox Development Highlights Articles
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Warp: Improved JS performance in Firefox 83
With Warp (also called WarpBuilder) we’re making big changes to our JIT (just-in-time) compilers, resulting in improved responsiveness, faster page loads and better memory usage. The new architecture is also more maintainable and unlocks additional SpiderMonkey improvements. This post explains how Warp works and how it made SpiderMonkey faster.
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Testing Firefox more efficiently with machine learning
A browser is an enormously complex piece of software, and it's always in development. About a year ago, we asked ourselves: how could we do better? Our CI relied heavily on human intervention. What if we could instead correlate patches to tests using historical regression data? Could we use a machine learning algorithm to figure out the optimal set of tests to run? We hypothesized that we could run fewer tests to save money, get results faster, and reduce the cognitive burden on developers.
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Adding prefers-contrast to Firefox
When we talk about the contrast of a page, or contrast between web elements, we’re assessing how color choices impact readability. For visitors with low vision, web pages with low or insufficient contrast can be hard to use. In this article, we’ll walk through the design and implementation of the
prefers-contrastmedia query in Firefox, and look at why it's so exciting and important. -
New in Firefox 78: DevTools improvements, new regex engine, and abundant web platform updates
Firefox 78 heads heads out the door with a new regex engine, updates to the ECMAScript Intl API, new CSS selectors, enhanced support for WebAssembly, some important WebExtensions API updates, and many improvements to the Firefox Developer Tools.
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A New RegExp Engine in SpiderMonkey
Regular expressions – commonly known as RegExps – are a powerful and heavily used tool for manipulating strings in JavaScript. This post describes how we updated the RegExp engine in SpiderMonkey, Firefox's JavaScript engine, by building a shim layer to V8's Irregexp. The outcome: reduced maintenance and stronger collaboration among the browsers, full support for all the new RegExp features, and compatibility with the latest ECMAScript standard.
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New in Firefox 77: DevTool improvements and web platform updates
Firefox 77 is now available with a variety of developer tool updates and new web platform features. With your feedback, we've removed performance bottlenecks, resulting in faster, leaner JavaScript debugging. We also report on some changes to Firefox extensions, including fewer permission requests.
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Building FunctionTrace, a graphical Python profiler
Firefox Profiler is a powerful web-based performance analysis interface featuring call trees, stack charts, flame graphs, and more. All data filtering, zooming, slicing, and transformation actions are preserved in shareable URLs. FunctionTrace is a low-overhead profiler that runs on unmodified Python applications. Integrated with Firefox, it's a new breed of analysis tool project built conveniently on top of the Firefox Profiler.
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Fuzzing Firefox with WebIDL
Fuzzing, or fuzz testing, is an automated approach for testing the safety and stability of software. For the past 3 years, the Firefox fuzzing team has been developing a new fuzzer to identify security vulnerabilities in the implementation of WebAPIs in Firefox. This fuzzer leverages the WebAPIs’ own WebIDL definitions as a fuzzing grammar.
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Engineering code quality in the Firefox browser: A look at our tools and challenges
Here's an insider's look at Firefox's code quality toolchain that's been designed to manage the ongoing development and monthly releases of our desktop browser. This post explores the architecture, challenges, and ongoing evolution of the process for managing code quality and patches for dealing with 21 million lines of code.
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Security means more with Firefox 74
The release of Firefox 74 is focused on security enhancements: Feature Policy, the Cross-Origin-Resource-Policy header, and removal of TLS 1.0/1.1 support. We’ve also got some new CSS text property features, the JS optional chaining operator, and additional 2D canvas text metric features, along with the usual wealth of DevTools enhancements and bug fixes.
