mongodb查询内部节点js eachOf循环

我想添加嵌套的DB查询内应该是一个eachOf循环同步。 尝试了这么多的组合，哪些没有为foreach循环内部工作。

async.eachOf(nc.virtual_devices, function (vd) { ///////// This code work fine ///////////// var domain = extractDomain(vd.api_url); vd.raw_api_ip = vd.api_ip; vd.api_ip = getProxiedPath(vd.api_ip); vd.raw_api_url = vd.api_url; vd.api_url = nconf.get('PROXIED_PATH_SCHEME') + vd.api_ip + vd.api_url.split(domain)[1]; // Path to websocket notifications vd.ws_url = nconf.get('PROXIED_PATH_SCHEME') + vd.api_ip + vd.notification_base_uri; //// THIS CODE IS NOT FINE ////////////// if (nc.type === 'XXX'){ var promise = new Promise (function (resolve,reject) { console.log("********XX VD TYPE **********"); console.log(JSON.stringify(vd)); console.log("VD ID VALUE IS ", vd.id); var newID = (vd.id).replace(/\d_/, ""); console.log("VD ID VALUE IS ", newID); var _idofSubgroup; var labeltoSearch = nc.type + ' ' + nc.version; pattern = "/^" + newID + "/i"; test = _idofSubgroup; pattern = newID; console.log(pattern); db.collection('subgroups').findOne({label: labeltoSearch}, function (err, result) { console.log(result._id); _idofSubgroup = result._id; db.collection('exploreposts').find({subgroup: result.id_}, {title: {"$regex": pattern}}).toArray(function (err, results) { console.log(results); }) }); }) } }); 

在里面承诺，但也在痛苦中。 这是我尝试的代码，这是行不通的。 任何build议，将不胜感激。简单地说，我一直卡在callback地狱

  async.eachOf(nc.virtual_devices, function (vd) { ///////// This code work fine ///////////// var domain = extractDomain(vd.api_url); vd.raw_api_ip = vd.api_ip; vd.api_ip = getProxiedPath(vd.api_ip); vd.raw_api_url = vd.api_url; vd.api_url = nconf.get('PROXIED_PATH_SCHEME') + vd.api_ip + vd.api_url.split(domain)[1]; // Path to websocket notifications vd.ws_url = nconf.get('PROXIED_PATH_SCHEME') + vd.api_ip + vd.notification_base_uri; //// THIS CODE IS NOT FINE with promises also ////////////// if (nc.type === 'XXX'){ var promise = new Promise (function (resolve,reject) { console.log("********XX VD TYPE **********"); console.log(JSON.stringify(vd)); console.log("VD ID VALUE IS ", vd.id); var newID = (vd.id).replace(/\d_/, ""); console.log("VD ID VALUE IS ", newID); var _idofSubgroup; var labeltoSearch = nc.type + ' ' + nc.version; pattern = "/^" + newID + "/i"; test = _idofSubgroup; pattern = newID; console.log(pattern); db.collection('subgroups').findOne({label: labeltoSearch}, function (err, result) { console.log(result._id); _idofSubgroup = result._id; resolve ({id_:_idofSubgroup,pattern1 : pattern}); }) }); promise.then (function(result) { console.log(result.id_); console.log(result.pattern1); db.collection('exploreposts').find({subgroup: result.id_}, {title: {"$regex": result.pattern1}}).toArray(function (err, results) { console.log(results); }) },function (err){ console.log (err); }) } }); 

Answer 1

似乎并不需要使用async.eachOf ，而是使用async.each（）或async.eachSeries（） 。

这是未经testing，但它看起来像

 async.eachSeries(nc.virtual_devices, function iteratee(vd, cb) { console.log('calling iteratee()') var domain = extractDomain(vd.api_url); vd.raw_api_ip = vd.api_ip; vd.api_ip = getProxiedPath(vd.api_ip); vd.raw_api_url = vd.api_url; vd.api_url = nconf.get('PROXIED_PATH_SCHEME') + vd.api_ip + vd.api_url.split(domain)[1]; // Path to websocket notifications vd.ws_url = nconf.get('PROXIED_PATH_SCHEME') + vd.api_ip + vd.notification_base_uri; // skip the rest if type is XXX; // you need to explicitedly call the original callback ie cb // note the use of return to prevent execution of the rest of the code if (nc.type !== 'XXX') return cb(null); // or cb(); console.log("********XX VD TYPE **********"); console.log(JSON.stringify(vd)); console.log("VD ID VALUE IS ", vd.id); var newID = (vd.id).replace(/\d_/, ""); console.log("VD ID VALUE IS ", newID); // I have no idea what is going here var _idofSubgroup; var labeltoSearch = nc.type + ' ' + nc.version; var pattern = "/^" + newID + "/i"; test = _idofSubgroup; pattern = newID; console.log(pattern); // we're going to use waterfall here as you have 2 async operations, where one is dependent on the other async.waterfall([ function getSubgroup(cb1) { console.log('calling getSubgroup') db.collection('subgroups').findOne({ label: labeltoSearch }, function (err, subgroup) { // if an error occurs, stop waterfall-loop // you do this by passing the error in the callback // again note the use of return here to prevent execution of the rest of the code if (err) return cb1(err); // pass the data to the next task cb1(null, subgroup, pattern); }); }, function getPosts(subgroup, pattern, cb2) { // we will only get here if the last task ^ went through console.log('calling getPosts') db.collection('exploreposts').find({ subgroup: subgroup._id, title: { $regex: pattern }}).toArray(function (err, posts) { // if an error occurs, stop waterfall-loop if (err) return cb2(err); // do something with posts console.log('posts', posts); // otherwise, keep going // since there are no more waterfall-tasks, waterfall ends cb2(); }); } ], function (err) { console.log('waterfall() done'); // if an error occurred during the waterfall-loop, it will come down here // we will let the original callback ie cb deal with this error though if (err) return cb(err); // otherwise we're done // we will let the original callback know everything went well by calling it without any error cb(); }); // you could have also simply do // ], cb); }, function (err) { console.log('eachSeries() done'); // handle any error that came console.log(err); // send response }); 

我故意命名这些variables和函数，以便您能够得到一个想法。

如果有任何问题，请按照日志。