Question

我遇到了async.each的问题，回调是在完成任务之前进行调用，我有下面的代码，得到输出为在调用reprice 6之前执行调用reprice 7,6是我在async.each回调中构建数组的部分

called reprice :
called reprice : 2
called reprice : 3
**called reprice : 7  []**
no chnages has been made 
called reprice : 6  { status: 200, msg: 'recived optimal price 4 ', data: 17.75 }
called reprice : 6  { status: 200, msg: 'recived optimal price 4 ', data: 20.99 }

这是代码

async.forEach(records, function(result, callback) {
    switch (result.Pricing) {
        case  "PF" : // current scenrio
            var pfObject = _.filter(rules, {'sub_title': 'PF'});
            checkRepriceFrequency(result, pfObject[0], function (response) {
                if (response.status === 200) {
                    // call check inventory rules
                    CheckInventoryRules(result, pfObject[0], function (response) {
                        console.log('called reprice : 6 ',response);
                        if (response.status === 200) {
                            var price = result.sales_price;
                            var pushData = {
                                price: price,
                                optimalPrice: response.data,
                                SKU: result.SKU,
                                _id: result._id,
                                frequency: pfObject[0].reprice_frequency
                            };
                            productArray.push(pushData);
                        }
                    });
                } else {
                    console.log('err');
                }
            });
        }
        callback(null);
    }, function(err) {
        console.log('called reprice : 7 ',productArray);
    if (!err) {
        if (productArray.length > 0) {
            console.log('To update Synch : ',productArray);
        } else {
            console.log("no chnages has been made ");
        }
    }
});

Answer 1

呀。所以你实施async.each有点不对劲。请参阅async.each确保每个对象都通过循环但不确保同步执行。在您的示例中，您调用了CheckInventoryRules，它似乎在进行AJAX调用。

但是检查一下，你已经在函数结束时调用了回调（它不等待AJAX完成）。这意味着在完成AJAX调用之前，回调可能被称为表明该特定对象的处理完成的信号。

要解决此问题，您需要检查是否正在调用AJAX调用，callback(null)之后需要调用productArray.push(pushData);。

通常，仅在任务完成执行时调用callback。

Answer 2

你已经完全错误地实现了async.forEach。 See this

交换机中似乎存在异步呼叫，因此您必须在该异步呼叫中呼叫 callback(null) 。

async.forEach(records, function(result, callback) {
    switch (result.Pricing) {
        case  "PF" :
            var pfObject = _.filter(rules, {'sub_title': 'PF'});
            checkRepriceFrequency(result, pfObject[0], function (response) {
                if (response.status === 200) {
                    CheckInventoryRules(result, pfObject[0], function (response) {
                        console.log('called reprice : 6 ',response);
                        if (response.status === 200) {
                            var price = result.sales_price;
                            var pushData = {
                                price: price,
                                optimalPrice: response.data,
                                SKU: result.SKU,
                                _id: result._id,
                                frequency: pfObject[0].reprice_frequency
                            };
                            productArray.push(pushData);
                            callback(null);
                        }
                    //handle callback on else otherwise final callback will not get the event.
                    });
                } else {
/*
                    callback(null);
                    Or
                    callback(Someerror);
*/
                    console.log('err');
                }
            });
            break;
        default:
            callback(null);
        // return false;


        //break;


    }


}, function(err) {
    console.log('called reprice : 7 ',productArray);
    if (!err) {
        if (productArray.length > 0) {
            console.log('To update Synch : ',productArray);

        } else {
            console.log("no chnages has been made ");
        }
    }
});

遇到async.each问题，回调就是在完成任务之前调用

2 个答案: