javascript - 嵌套 Node async.eachSeries

Question

和async module纠缠了半天，嵌套的层数少，还是无法正常工作。

所以这工作正常:

    var async = require('async')    var myarr = ["Outer - A", "Outer - B"];    var myarr2 = ["Inner - A", "Inner - B"];    var innerComplete = true;    async.eachSeries(myarr, function( item, outerCallback) {        console.log('Processing item ' + item);        async.series([            function(callback) {                takeTime(2000, item, callback)            },            function(callback) {                takeTime(1000, item, callback)            },            function(callback) {                outerCallback();            }        ], function(err) {            console.log("---OUTER SEQUENCE---")        })    }, function(err){        console.log("---OUTER LOOP---")    });    function takeTime(ms, msg, callback) {        console.log("Starting " + ms + " ms task from " + msg);        setTimeout( function() {             console.log("Finished " + ms + " ms task from " + msg);            callback();        }, ms);    } 

它会像这样按顺序很好地输出所有内容:

Processing item Outer - AStarting 2000 ms task from Outer - AFinished 2000 ms task from Outer - AStarting 1000 ms task from Outer - AFinished 1000 ms task from Outer - AProcessing item Outer - BStarting 2000 ms task from Outer - BFinished 2000 ms task from Outer - BStarting 1000 ms task from Outer - BFinished 1000 ms task from Outer - B---OUTER LOOP---

但是当我尝试像这样嵌套另一个 eachSeries 循环时:

    var async = require('async')    var myarr = ["Outer - A", "Outer - B"];    var myarr2 = ["Inner - A", "Inner - B"];    var innerComplete = true;    async.eachSeries(myarr, function( item, outerCallback) {        console.log('Processing item ' + item);        async.series([            function(callback) {                takeTime(2000, item, callback)            },            function(callback) {                takeTime(1000, item, callback)            },            function(callback) {                async.eachSeries(myarr2, function( item2, outerCallback2) {                    console.log('Processing item ' + item2);                    async.series([                        function(callback2) {                            takeTime(2000, item2, callback2)                        },                        function(callback2) {                            takeTime(1000, item2, callback2)                        }                    ], function(err) {                        console.log('---INNER SEQUENCE---')                    })                }, function(err){                    console.log("---INNER LOOP---")                });                outerCallback();            }        ], function(err) {            console.log("---OUTER SEQUENCE---")        })    }, function(err){        console.log("---OUTER LOOP---")    });    function takeTime(ms, msg, callback) {        console.log("Starting " + ms + " ms task from " + msg);        setTimeout( function() {             console.log("Finished " + ms + " ms task from " + msg);            callback();        }, ms);    } 

它在进入第二个 eachSeries 循环时丢失了执行顺序，如下所示:

Processing item Outer - AStarting 2000 ms task from Outer - AFinished 2000 ms task from Outer - AStarting 1000 ms task from Outer - AFinished 1000 ms task from Outer - AProcessing item Inner - AStarting 2000 ms task from Inner - AProcessing item Outer - BStarting 2000 ms task from Outer - BFinished 2000 ms task from Inner - AStarting 1000 ms task from Inner - AFinished 2000 ms task from Outer - BStarting 1000 ms task from Outer - BFinished 1000 ms task from Inner - A---INNER SEQUENCE---Finished 1000 ms task from Outer - BProcessing item Inner - AStarting 2000 ms task from Inner - A---OUTER LOOP---Finished 2000 ms task from Inner - AStarting 1000 ms task from Inner - AFinished 1000 ms task from Inner - A---INNER SEQUENCE---

我还尝试了 waterfall 、mapSeries 等，但执行顺序相同或困惑。是我做错了什么还是异步模块不支持这种嵌套？

Answer 1

您没有调用 outerCallback2，您没有调用 callback，而是立即调用了 outerCallback。

固定:

async.eachSeries(myarr, function( item, outerCallback) {
  ,----------------------------------------'
  |  console.log('Processing item ' + item);
  |  async.series([
  |      function(callback) {
  |                 `--------------,
  |          takeTime(2000, item, callback)
  |      },
  |      function(callback) {
  |                 `--------------,
  |          takeTime(1000, item, callback)
  |      },
  |      function(callback) {
  |     ,-----------'
  |     |     async.eachSeries(myarr2, function( item2, outerCallback2) {
  |     |    ,---------------------------------------------'
  |     |    |   console.log('Processing item ' + item2);
  |     |    |   async.series([
  |     |    |      function(callback2) {
  |     |    |          takeTime(2000, item2, callback2)
  |     |    |      },
  |     |    |      function(callback2) {
  |     |    |          takeTime(1000, item2, callback2)
  |     |    |      }
  |     |    |  ], function(err) {
  |     |    |      console.log('---INNER SEQUENCE---')
  |     |    `--->  outerCallback2(err); // <<<
  |     |       })
  |     |   }, function(err){
  |     |      console.log("---INNER LOOP---");
  |     `--->  callback(err); // <<<
  |         });
  |     }
  | ], function(err) {
  |      console.log("---OUTER SEQUENCE---")
  `--->  outerCallback(err); // <<<
    })
}, function(err){
    console.log("---OUTER LOOP---")
    console.log("everything done");
});