SimpleLayoutWorlet.js

class SimpleLayoutWorlet
    *intrinsicSizes() {}
   
    *layout(children, edges, constraintSpace, styles) {
      const childFragments = []
     
      for(const child of children) {
        const childFragment = yield child.layoutNextFragment();
        ...
      }

      return {
        childFragments
      };
    }
}

registerLayout('simpleLayout', SimpleLayoutWorlet);