Node.js/Javascript - 等待方法完成

我正在寫一個蒸汽交易機器人，但我有問題，for循環不會等到for循環內的方法完成。所以代碼不能像它應該那樣工作。Node.js/Javascript - 等待方法完成

for (i = 0; i < offer.itemsToReceive.length; i++) { 

    console.log(offer.itemsToReceive[i].market_hash_name); 

    community.getMarketItem(appid.CSGO, offer.itemsToReceive[i].market_hash_name, function(err, items) { 
     if (err) { 
      Winston.error("Error getting Marketprice"); 
     } else { 
      var cacheItemPrice = items.lowestPrice; 
      totalValue += items.lowestPrice; 
      Winston.info("Item " + offer.itemsToReceive[i].market_hash_name + " is " + items.lowestPrice + " Cents worth"); 
      if (items.lowestPrice <= minValue) { 
       minValue = items.lowestPrice; 
      } 
     } 

    }); 
}

如果循環不等待，直到方法完成，變量i是不是在正確的方法，我得到一個錯誤的結果。

編輯：
現在，當我把從@Cleiton代碼到我的函數，即我要回兩個值，函數返回值的方法有時間來改變他們。

function checkItemPricesCashIn(offer) { 
    Winston.info("Getting itemprices from trade #" + offer.id); 
    var totalValue = 0; 
    var minValue = 50; 

    var executionList = []; 

    function getMarketItem(item) { 
     var market_hash_name = item.market_hash_name; 
     return function() { 
      community.getMarketItem(appid.CSGO, market_hash_name, function(err, items) { 
       if (err) { 
        Winston.error("Error getting Marketprice"); 
       } else { 
        var cacheItemPrice = items.lowestPrice; 
        totalValue += items.lowestPrice; 
        Winston.info("Item " + market_hash_name + " is " + items.lowestPrice + " Cents worth"); 
        if (items.lowestPrice <= minValue) { 
         minValue = items.lowestPrice; 
        } 
       } 
       (executionList.shift() || function() {})(); 
      }); 
     } 
    } 

    offer.itemsToReceive.forEach(function(item) { 
     executionList.push(getMarketItem(item)); 
    }); 

    if (executionList.length) { 
     executionList.shift()(); 
    } 

    console.log(totalValue); 
    console.log(minValue); 

    return { 
     totalValue: totalValue, 
     minValue: minValue 
    } 
}

來源

2015-11-30 jeanggi90

下面是一個完整的工作代碼，我希望這有助於:)

function checkItemPricesCashIn(offer, cb) { 
 
Winston.info("Getting itemprices from trade #" + offer.id); 
 
var totalValue = 0; 
 
var minValue = 50; 
 

 
var executionList = []; 
 

 
function getMarketItem(item) { 
 
    var market_hash_name = item.market_hash_name; 
 
    return function() { 
 
     community.getMarketItem(appid.CSGO, market_hash_name, function(err, items) { 
 
      if (err) { 
 
       Winston.error("Error getting Marketprice"); 
 
      } else { 
 
       var cacheItemPrice = items.lowestPrice; 
 
       totalValue += items.lowestPrice; 
 
       Winston.info("Item " + market_hash_name + " is " + items.lowestPrice + " Cents worth"); 
 
       if (items.lowestPrice <= minValue) { 
 
        minValue = items.lowestPrice; 
 
       } 
 
      } 
 
      (executionList.shift() || cb)(minValue,totalValue); 
 
     }); 
 
    } 
 
} 
 

 
offer.itemsToReceive.forEach(function(item) { 
 
    executionList.push(getMarketItem(item)); 
 
}); 
 

 
if (executionList.length) { 
 
    executionList.shift()(); 
 
} 
 
}

如何使用：

checkItemPricesCashIn(yourOffer/*your offer*/, function(min, max){ 
//it will be execute just after 
console.log('min', min); 
console.log('max', max); 

});

來源

2015-11-30 23:06:23 Cleiton

感謝此代碼。但現在，當我將這段代碼放入函數中返回總值和最小值時，該函數在方法可以改變它們之前返回值。見上面編輯... – jeanggi90

看我的更新，希望這個幫助 – Cleiton

您可以使用一些庫作爲async https://github.com/caolan/async。並且每個系列或者每個系列都有一個異步週期。

async.each(array, function(item, callback){ 
 
    // do something with a item 
 
    // call callback when finished 
 
    callback(); 
 
});

來源

2015-11-30 23:02:56

Node.js/Javascript - 等待方法完成

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