Main Thread Runtime#

PrimJS#

The main thread uses PrimJS as the runtime engine. PrimJS is a lightweight, high-performance JavaScript engine designed specifically for Lynx. PrimJS is built on top of QuickJS and offers a much better performance and development experience than QuickJS. experience compared to QuickJS.

Meanwhile, PrimJS provides a high-performance FFI capability, which can encapsulate the Lynx object as a JS object and return it to the FFI caller at low cost, which has obvious performance advantage over the traditional FFI. However, this type of JS object is not an Object Model, Lynx engine can not bind setter getter methods to this object, it can only provide FFI to pass it as a parameter to realize similar functions.

Element PAPI Bindings#

In order to achieve high performance, the Element PAPI provided in the main thread runtime is based on the above approach. Since ReactLynx developers don't need to manipulate Element directly in most scenarios, this limitation of high-performance FFI doesn't degrade the experience.

If developers need to operate Element directly, we provide the main-thread-element based on the Element PAPI to improve the development experience.

Lynx API Bindings#

Because of the special nature of the main thread, we only provide Lynx APIs in the main thread that do not affect rendering, which are a subset of the background thread APIs.

Runtime Script Format#

For performance optimization, the main thread scripts use the bytecode format compiled by PrimJS. This format avoids the parsing of scripts at runtime, and the bytecode format can be loaded about four times faster than normal text format scripts.