uniappx 将any类型转为自定义type类型，只有APP模式下编译报错，输出结果为空

type httpResponseProcessCategoryData = {
code: number;
data: ProcessCategoryData[] | null;
msg: string;
}

接口返回res是any类型，做了转换
let result : httpResponseProcessCategoryData | null = JSON.parse<httpResponseProcessCategoryData>(JSON.stringify(res))
console.log('result。。。', result);
输出result为空?为什么？？？