javascript - NodeJS 异步/等待 + 快速请求递归

Question

我有一个名为 GetAllData() 的函数，它调用 GetPurchaseData，该函数会递归调用自身，直到加载所有数据。在

async function GetAllData(){
    console.log("starting loading purchase data");
        await GetPurchaseData();
        console.log("purchase data loaded")        
}

async function GetPurchaseData(){
         return new Promise(async function (resolve,reject){
            var Headers = {
                ....
            }
            await request({url: xxx, headers: Headers },async function(error, response, body) {
                    var tmp = JSON.parse(body)      
                    _.forEach(tmp.Purchases, p => purchaseData.push(p));                          

                    if (response.headers.pagination){
                        return await GetPurchasePaginatedData()
                    }
                    else{
                        console.log("done loading....")
                        return resolve("done")
                    }
            });
        })
}

Node JS 打印以下输出:

starting loading purchase data 
done loading....

但它永远不会返回到 GetAllData 进行打印

purchase data loaded

它看起来几乎陷入了功能困境，但我的观点是，不知何故，“returnsolve("done")”行并没有回到最初的调用以实际将 Promise 标记为完成。

>

Answer 1

避免 async/await Promise constructor antipattern (另请参阅 here )，并避免将 async 函数作为常规回调传递 - 您需要 use the Promise constructor to promisify an existing callback API !

async function GetPurchaseData() {
    var headers = {…};
    var promise = new Promise((resolve,reject) => { // not async!
        request({url: xxx, headers}, (error, response, body) => { // not async!
            if (error) reject(error);
            else resolve({response, body});
        });
    }); // that's it!

    var {response, body} = await promise;
    for (var p of JSON.parse(body).Purchases)
        purchaseData.push(p));                          

    if (response.headers.pagination) {
        return GetPurchasePaginatedData()
    } else {
        console.log("done loading....")
        return "done";
    }
}