让我们考虑一个例子，导入对象看起来像这样:
const importObject = {
exampleAsyncImportFunction: async () => fs.readFile("./someExampleFile.txt", "utf-8") // returns Promise<String>
};
我想在我的 rust 迹斑斑的WASM模块中使用它，类似于:
#[wasm_bindgen]
extern "C" {
pub async fn exampleAsyncImportFunction() -> JsValue; // Importing the JS-Function
}
#[wasm_bindgen]
pub async fn exampleExportFunction() -> Result<JsValue, JsValue> {
let theJSPromise = exampleAsyncImportFunction(); // Call the async import function
let promiseResult = theJSPromise.await; // Execute the async import function
// Do sth with the result
OK(JsValue::UNDEFINED)
}
不幸的是，这会导致无法到达的错误.有趣的是，当JavaScript函数返回一个字符串时，它确实可以工作，如下所示:
const importObject = {
exampleAsyncImportFunction: async () => "Some dummy content" // returns Promise<String> as well
};
当然，异步导入函数应该执行一些实际的异步任务，否则最好使用同步函数.
I tried to do some research and found 'js_sys::Promise' which represents a JS-Promise in Rust, and 'wasm_bindgen_futures::JsFuture' which enables to somehow convert a JS-Promise to a Rust-Future. But I don't understand, if/how these types may help with the problem and also how they should be used in general in this context.
Also it seems, that the return type of the JS-Import-Function, which is 'JsValue' by declaration, somehow implements the 'Future'-Trait. I understand that due to that, 'awaiting' the result is possible. But I'm confused, what's the actual underlying type (JsFuture, Promise, something else...).
我希望有人能在这方面帮助我，解决实际问题，同时解释一下所有类型之间的关系(尤其是关于JsValue).
提前谢谢！