如何重新使用異步回調函數？

Question

我在具有相同回調函數 的兩個函數中使用async.parallel。在第二功能（two()）加入第三功能加法功能

function one(){ 
var testuser = 1; 
async.parallel([onefunction, secondfunction], function(err, result){...}) 
} 

function two(){ 
var testuser = 2; 
async.parallel([onefunction, secondfunction, thirdfunction], function(err, result){...}) 
} 

function onefunction(callback){....code with testuser......} 
function twofunction(callback){....code with testuser......} 
function thirdfunction(callback){....code with testuser......} 

Q：如何可在onefunction，secondfunction和thirdfunction訪問TESTUSER值。

現在我得到undefined err。我也嘗試了正常參數傳遞邏輯onefunction(testuser)，但它不工作。

我想在多種情況下使用onefunctiontwofunction ......我該怎麼做？

Answer 1

作爲@Felix建議，

function one(){ 
var testuser = 1; 
async.parallel([onefunction, secondfunction], function(err, result){...}) 
} 

    function two(){ 
    var testuser = 2; 
    async.parallel([ 
     callback => onefunction(testuser, callback), 
     callback => twofunction(testuser, callback), 
     callback => thirdfunction(testuser, callback)], function(err, result){...}) 
    } 

    function onefunction(callback){....code with testuser......} 
    function twofunction(callback){....code with testuser......} 
    function thirdfunction(callback){....code with testuser......} 

Answer 2

這是我怎麼能在onefunction，secondfunction &等訪問testuser值..
代碼：

var async = require('async'); 

function one(){ 
    var testuser = 1; 
    //You can bind a context here; remember to pass the context i.e. null for this, otherwise it won't work as expected. 
    async.parallel({one_func:onefunction.bind(null,testuser), two_func:twofunction.bind(null,testuser)}, function(err, result){ 
     console.log("In one()"); 
     console.log("err",err); 
     console.log("result",result); //result array with all task's results e.g. one_func, two_func 
     console.log("testuser",testuser); 
}) 
} 

function onefunction(testuser,cb){ 
    console.log('onefunction'); 
    return cb(null,{"testuser":testuser}); 
} 

function twofunction(testuser,cb){ 
    console.log('twofunction'); 
    return cb(null,{"testuser":testuser}); 
} 

one(); 

更新：答案在約重用回調標題您的另一個問題。
您可以重新使用命名函數作爲回調？
示例代碼：

function one(){ 
    var testuser = 1; 
    async.parallel({one_func:onefunction.bind(null,testuser), two_func:twofunction.bind(null,testuser)},calback) 
} 

function calback (err, result){ 
     console.log("calback"); //You can reuse this named function as callbacks 
     console.log("err",err); 
     console.log("result",result); 
}