javascript - 未定义flatbuffers

我正在编写一个使用Google Flat缓冲区的nodeJs应用程序。

我在macbook pro上安装了flatc并编译了以下架构：

命名空间MyAlcoholist;

table Drink {
 drink_type_name: string;
 drink_company_name: string;
 drink_brand_name: string;
 drink_flavor_type_name : string;
 liquid_color_type_name : string;
 liquid_color_is_transparent : bool;
 alcohol_vol : float;
 calories_for_100g : uint;
 global_image_id: ulong;
 drink_flavor_id: ulong;
}

table Drinks { drinks:[Drink]; }

root_type Drinks;

该架构文件称为Drink.fbs，并生成了一个名为Drink_genic.js的javascript文件

我将此文件包含在我的nodejs应用程序中，并使用以下代码向其中添加数据。这是我的flatBufferUtil.js实用程序文件。

var flatbuffers = require('../js/flatbuffers').flatbuffers;
var builder = new flatbuffers.Builder();

var drinks = require('../fbs/drinks_generated').MyAlcoholist; // Generated by `flatc`.

function drinkArrayToBuffer(drinkArray) {
var drinksVectArray = [];
drinkArray.forEach(function (element, index, array) {
    var drinkObj = element;
    var drinkBrandName = builder.createString(drinkObj.drink_brand_name);
    var drinkCompanyName = builder.createString(drinkObj.drink_company_name);
    var drinkflavorTypeName = builder.createString(drinkObj.drink_flavor_type_name);
    var drinkTypeName = builder.createString(drinkObj.drink_type_name);
    var liquidColorTypeName = builder.createString(drinkObj.liquid_color_type_name);
    drinks.Drink.startDrink(builder);
    drinks.Drink.addAlcoholVol(builder, drinkObj.alcohol_vol);
    drinks.Drink.addCaloriesFor100g(builder,drinkObj.calories_for_100g);
    drinks.Drink.addDrinkBrandName(builder,drinkBrandName);
    drinks.Drink.addDrinkCompanyName(builder,drinkCompanyName);
    drinks.Drink.addDrinkFlavorId(builder,drinkObj.drink_flavor_id);
    drinks.Drink.addDrinkFlavorTypeName(builder, drinkflavorTypeName);
    drinks.Drink.addDrinkTypeName(builder,drinkTypeName);
    drinks.Drink.addGlobalImageId(builder,drinkObj.global_image_id);
    drinks.Drink.addLiquidColorIsTransparent(builder,drinkObj.is_transparent);
    drinks.Drink.addLiquidColorTypeName(builder,liquidColorTypeName);
    var drink = drinks.Drink.endDrink(builder);
    drinksVectArray.push(drink);
})
var drinksVect = drinks.createDrinksVector(builder,drinksVectArray);
builder.finish(drinksVect);
var buf = builder.dataBuffer();
return buf;
}

module.exports.drinkArrayToBuffer=drinkArrayToBuffer;

现在，当我执行此功能时，它将失败，并显示错误flatbuffers is not defined。

我调试了代码，然后看到它在以下代码行中归档：

    drinks.Drink.addDrinkFlavorId(builder,drinkObj.drink_flavor_id);

如果我进入addDrinkFlavorId函数，则会在Drinks_generted.js中看到以下代码：

MyAlcoholist.Drink.addDrinkFlavorId = function(builder, drinkFlavorId) {
   builder.addFieldInt64(9, drinkFlavorId, flatbuffers.Long.ZERO);
};

如您所见，它使用flatbuffers.Long.ZERO，但是该文件中根本没有定义flatbuffers。编译没有提供任何错误，所以我想念什么？

最佳答案

在我看来，这似乎是一个错误。...生成的文件似乎应从flatbuffers需求自动存在。但是，对于自定义的flatbuffers.Long类，默认的flatbuffers.Long.ZERO会渗入生成的文件中。

虽然这不是一种解决方案，但一种解决方法是将所需的Flatbuffer手动添加到生成的文件中。这很丑陋，但是总比被阻止直到有更合适的答案（或解决方案）更好。

// In `drinks_generated.js`
var flatbuffers = require('../js/flatbuffers').flatbuffers;

注意：

drinks.Drink.addDrinkFlavorId()和drinks.Drink.addGlobalImageId()函数希望将flatbuffers.Long值传递给它们，因为在模式（ulong文件）中将它们指定为fbs。因此，您需要确保您不尝试传递简单的number类型。

例如：

var my_long = flatbuffers.Long(100, 0); // low = 100, high = 0
drinks.Drink.addDrinkFlavorId(builder, my_long);

因此，另一种可能的解决方法是更改架构中那些字段的数据类型，以免使用ulong直到更清楚这里发生了什么。

附言我很确定该摘要的第30行上的drinks.createDrinksVector应该是drinks.Drinks.createDrinksVector。