安卓下使用defineProps泛型传入嵌套的自定义类型时出现报错，请问如何解决

先放代码

    type ITest={  
        aa?:string,  
        bb?:string  
    }  
    type IProps = {  
        styles ?: ITest  
    }  

    const props = withDefaults(defineProps<IProps>(), {  
        styles:():ITest=>({}),  
    })

出现报错
Cannot create property 'code' on string 'load_transformed failed
19:45:14.249 Caused by:
19:45:14.249 0: Bundler.load() failed
19:45:14.249 1: Bundler.loader.load(D:\Code\jui\jui\unpackage\dist\dev.uvue\uni_modules\j-ui\components\j-navbar\j-navbar.uvue) failed
19:45:14.249 2:
19:45:14.249 x Expected ',', got '?'
19:45:14.249 at uni_modules/j-ui/components/j-navbar/j-navbar.uvue:17:1
19:45:14.249 14 | export default {
19:45:14.249 15 | name: 'j-navbar',
19:45:14.250 16 | props: {
19:45:14.250 17 | styles: { type: [Object as PropType<aa?:string,>, Object as PropType<bb?:string>], required: false, default: ():ITest=>({}) }
19:45:14.250 : ^
19:45:14.250 18 | },
19:45:14.250 19 | emits: ["ratioChange"],
19:45:14.250 20 | setup(props: GenUniModulesJUiComponentsJNavbarJNavbar) {
19:45:14.250 `----
19:45:14.250
19:45:14.250 3: Syntax Error'

环境：win11 hbuilder：4.24 安卓模拟器运行 标准基座
请问这种情况如何解决？