SAILS 0.10：保存到數據庫時出現Async＆Promise問題

看起來我對promise有異議。我已經測試了sails-mysql，sails-mongo，sails-postgres版本0.10-rc-XX，並且問題發生了。但是當我使用sails-disk時，沒有問題。看看我的意見如下SAILS 0.10：保存到數據庫時出現Async＆Promise問題

var storeInvoiceDetail = function(detail) { 
    return function(cb) { 
    cb(null, detail); 
    }; 
} 

var getPreviousDetail = ['storeInvoiceDetail', function(cb, results) { 
    var invoiceDetail = results.storeInvoiceDetail; 

    PreviousDetail 
    .findOne({ 
     invoice: invoiceDetail.invoice, 
     product: invoiceDetail.product.id 
    }) 
    .sort('createdAt desc') 
    .exec(cb); 
}]; 

var createPreviousDetail = ['storeInvoiceDetail', function(cb, results) { 
    var invoiceDetail = results.storeInvoiceDetail; 

    PreviousDetail 
    .create({ 
     invoice: invoiceDetail.invoice, 
     product: invoiceDetail.product.id, 
     quantity: invoiceDetail.quantity 
    }) 
    .exec(cb); 
}]; 

var getStockDifference = ['storeInvoiceDetail', 'getPreviousDetail', function(cb, results) { 
    var difference = results.storeInvoiceDetail.quantity - results.getPreviousDetail.quantity; 

    cb(null, difference); 
}]; 

// see here 
var updateProductStock = ['getPreviousDetail', 'getStockDifference', function(cb, results) { 
    Product 
    .findOne(results.getPreviousDetail.product) 
    .then(function(product) { 
     // imagine the value of 'results.getStockDifference' is 5 
     product.stock += results.getStockDifference; 
     product.save(); 

     // when I do log, the output is: 5, but this value is not updated to database 
     // It seems 'product.save()' at above is not called 
     // maybe this code have issues with 'async' & 'promise' 
     // anybody know how to correct this? 
     console.log(product.stock); 
     cb(null, product.stock); 
    }); 
}]; 

exports.updateProductStock = function (details) { 
    var beforeModifyProductStock = {}; 

    async.each(details, function(detail, callback) { 
    beforeModifyProductStock = { 
     storeInvoiceDetail: storeInvoiceDetail(detail), 
     getPreviousDetail: getPreviousDetail, 
     createPreviousDetail: createPreviousDetail, 
     getStockDifference: getStockDifference, 
     updateProductStock: updateProductStock 
    }; 

    async.auto(beforeModifyProductStock, function(err, results) { 
     console.log('now latest stock is ' + results.updateProductStock); 
     callback(); 
    }); 

    }, function (err) { 
    // no action 
    }); 
}

來源

2014-06-22 user3741665

你爲什麼在這裏使用'async'？你已經在你的代碼中擁有更強大的承諾... –

@Benjamin因爲我想迭代'細節'變量並將其拋入'updateProductStock'函數。它是異步的，所以我不能使用_.each。你介意，如果你給我的例子只使用'承諾'？ – user3741665

.save()是一種異步方法。重寫你的updateProductStock功能爲：

var updateProductStock = ['getPreviousDetail', 'getStockDifference', function(cb, results) { 
    Product 
    .findOne(results.getPreviousDetail.product) 
    .then(function(product) { 
     product.stock += results.getStockDifference; 
     // Note the callback argument to .save() 
     product.save(function(err, product) { 
      console.log(product.stock); 
      cb(err, product.stock); 
     });  
    }); 
}];

你應該沒問題。

來源

2014-06-26 22:36:52 sgress454

SAILS 0.10：保存到數據庫時出現Async＆Promise問題

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