JavaScriptCore is a built-in iOS library that enables you to use JavaScript in apps alongside Objective-C and Swift. It lets developers read JavaScript from a string, execute it from Objective-C or Swift, and share data structures and functions across languages. We JavaScriptCore to share code between Web and iOS.
Sharing code helped us produce a high-quality, consistent experience across devices while iterating rapidly.
This post is about why we chose to use JavaScriptCore and what we learned. The biggest challenges to using JavaScriptCore in a production app were performance optimization for older devices and getting the build process right. Luckily, these problems have simple solutions that just weren't documented.
A killer feature of one of our apps is search that is optimized for finding guests by name. Our goals included: