npm模块async。从上一个函数获取返回值

Question

npm install async

示例：

    var async = require('async');   
    var a = function(callback)
    {
        console.log("Hello ");
        callback(null,'vals1')
        return 'prop' 
    };
    var b = function(callback)
    {  
        //I want get  return 'prop'  from a() its posible ?
        console.log("World");
         callback(null,"vals2")
    };
    async.series(
    [
        a,b
    ],function(err,vals){
        console.log(vals) //[val1,vals2]
        console.log('finals')
    }
        );

我想从a（）返回'prop'到b（）。它的可能性？ 谢谢......

Answer 1

// Pretend this is some complicated async factory
async.waterfall([
    function(callback){
        console.log('1');
        callback(null, 'one', 'two');
    },
    function(arg1, arg2, callback){
        console.log('2::::::' + arg1 + arg2 +':::')
      // arg1 now equals 'one' and arg2 now equals 'two'
        callback(null, 'three');
    },
    function(arg1, callback){
        // arg1 now equals 'three'

        console.log('3::::::' + arg1 )
        callback(null, 'done');
    }
], function (err, result) {
   console.log(result);  
});