for 循环中的 node.js 回调

Question

我正在尝试读取一些数据并将其放入多数组中。要打开不同的文件，我使用 for 循环，因为我需要以正确的顺序对结果进行编号。我的问题:

我无法将数据保存在一个数组中。一旦我调用函数来读取数据，我只能在函数边界内使用结果。如何使整个数组在此函数之外可用？ (很确定我搞乱了回调)。

换句话说:我正在尝试打开多个文件并将内容保存在一个数组 [[file1], [file2], ...] 中。

这是我的代码:

var einlesen = require ('./einlesen/einlesen.js');

var einzeln = function(arg, callback){   //this is the function I use to read the data (it works fine, I checked it separately)
    einlesen.einlesen(arg[0], arg[1], arg[2], function(err, output){  //this function opens a file, works on the content and returns an array containing the needed data
        if (err) { return cb1(err); }
        callback(output);
    });
}

var daten_einlesen = function (callback){

    var tabellenarray = []; //initiating the array in which the whole info should go
    var tabelleninfos = [   //this array contains the info which data should be read, you only need to know that there are 16 files to be read, the rest is not important
                            ['gvz', '<|>', '1,1,1,0,1,0,0,0,1'], 
                            ['GZV', ';', '1,1,1,1,1,1,1,1'], 
                            ['XPG', ';', '1,1,1,1,1'], 
                            ['ABF', ';', '1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1'], 
                            ['GUS', '<|>', '1,1,0,1,0,0,0,0,1,1,1'], 
                            ['XPA', '<|>', '1,1,1'], 
                            ['ALW', '<|>', '1,1,1'], 
                            ['TAL', '<|>', '1,1,1'], 
                            ['ALB', '<|>', '1,1,0,1,1,1,1,1,1'], 
                            ['ZLB', '<|>', '1,1,1'], 
                            ['XAW', '<|>', '1,1,1'], 
                            ['SWS', ';', '1,1,1,1,1,1,1,1,1,1'], 
                            ['PRO', '<|>', '1,1'], 
                            ['VBP', '<|>', '1,0,1'], 
                            ['ZVP', '<|>', '1,1,1'],
                            ['config', ';', '0,0,1']];

    for (var i = 0; i < 3; i++){  //this is the loop where i try to open the files one by one and input them into the "tabellenarray"
        einzeln(tabelleninfos[i], function(tabelle){
            tabellenarray[i] = tabelle; //data is saved to the array but I lose the info onto the next step of the loop, if i put the final callback (below) in here the loop doesnt work anymore (naturally)
        });
    }       
    callback(tabellenarray);
}

daten_einlesen(function(piep){ //calling the whole function
console.log(piep);
});

我很感激任何建议。

尼尔斯

Answer 1

首先尝试一下这个:

var pending = 3,complete=0;
for (var i = 0; i < pending; i++){  //this is the loop where i try to open the files one by one    and input them into the "tabellenarray"
    einzeln(tabelleninfos[i], function(tabelle){
        tabellenarray[i] = tabelle; //data is saved to the array but I lose the info onto the next step of the loop, if i put the final callback (below) in here the loop doesnt work anymore (naturally)
        if(++complete >= pending){
            callback(tabellenarray);
        }
    });
}