Question

守则

我尝试使用此程序包https://www.npmjs.com/package/async来实现系列＆amp;并行处理。

对于小案例，它很有效，但是当我尝试运行它时，我得到了一个意想不到的行为：

async.series([
    function(callback){
        console.log('one');
        callback();
    },
    function(callback){
        console.log('two');
        async.parallel([
            function(callback){
                console.log('two-one');
                callback();
            },
            function(callback){
                async.series([
                    function (callback){
                        console.log('two-two-one');
                        callback();
                    },
                    function (callback){
                        console.log('two-two-two');
                        callback();
                    }
                ]);
            }
        ], callback);
    },
    function(callback){
        console.log('three');
        callback();
    }
]);

预期结果

代码应该串联打印one，two，two-one和three。但是，在打印two-one后，我想要并行打印two-two-one和two-two-two。

预期结果是：

one
two
two-one
two-two-one
two-two-two
three

或

one
two
two-one
two-two-two
two-two-one
three

真实结果

不幸的是，永远不会打印three。

one
two
two-one
two-two-one
two-two-two

问题

我的代码/理解有问题吗？

感谢。

Answer 1

异步系列将最后一个参数作为函数来获取最终结果。

请将并行回调作为异步系列的第二个参数传递。

async.series([
    function(callback){
        console.log('one');
        callback();
    },
    function(callback){
        console.log('two');
        async.parallel([
            function(callback){
                console.log('two-one');
                callback();
            },
            function(callback){
                async.series([
                    function (callback){
                        console.log('two-two-one');
                        callback();
                    },
                    function (callback){
                        console.log('two-two-two');
                        callback();
                    }
                ],callback);// pass parallel callback to trace the outcome 
            }
        ], callback);
    },
    function(callback){
        console.log('three');
        callback();
    }
],console.log);// use console.lg to get the final outcome of series

node-async不执行回调

1 个答案: