TypeError: task is not a function in async js parrallel

问题:

I am trying to upload an image and update the url of the image in the database collection using the code below.

Controller.prototype.handle = function (req, res, next) {   var id = req.params.id,       controller = req.params.controller,       optionalController;    optionalController = _.clone(controller);    // handle optional controller   if (controller === 'newboat') {     controller = 'boat';   } else if (controller === 'newcrew') {     controller = 'crew';   }    var files = req.files.files || {},       monthYear = new Date(),                 monthYear = [monthYear.getFullYear(), monthYear.getMonth()],             filename = files[0].originalFilename,       path = files[0].path,       extension = filename.match(EXPRESSION_EXTENSION)[1],       destFolder = [ROOT, monthYear[0], '/', monthYear[1] ].join(''),       destination = [ROOT, monthYear[0], '/', monthYear[1] ,'/', id, '.', extension ].join('');          // log info     //console.log(id, controller, filename, extension, destination, path);    var opts = JSON.stringify({id: id, photo: ['/uploads/',monthYear[0], '/', monthYear[1] ,'/', id, '.', extension ].join('') });    async.series([                 uploadImage(path,destFolder,destination),                  ProcessUpload(optionalController, opts, res)                ]); };  // write file var uploadImage = function(path,destFolder, destination) {     // The land of callbacks ------>>>>>> inception within inception     mkdirp(destFolder,777,function (err) {              fs.readFile(path, function (err, data) {            fs.writeFile(destination, data, function (err) {                 if (err) {                     console.log('image not uploaded..');                     return false;                 }else {                   return true;                 }             });         });     });   };   var ProcessUpload = function(optionalController, opts, res ) {    opts = JSON.parse(opts);    if (optionalController === 'boat') {         updateBoatDatabase(opts);       }  };  /**  * Update boat photo to database  */ var updateBoatDatabase = function (opts, callback) {   // save to database   return dbServices.dbBoat.updatePhoto(opts, callback); }; 

Here is the Database Service that is being called

  /**    * Update image    */   updatePhoto: function (opts, callback) {     var id = opts.id;      // find boat by id     this.modelClass.findById(id, function (err, model) {       if (err || !model)         return callback(err);              // set update value       model.photo = opts.photo;        // save       model.save(callback);     });   }, 

I get the following error in uploading the image but the image gets uploaded on the server and its url updated on the database collection as well. I am assuming that it has to do with my callbacks but I am not really sure where I am going wrong. Any tips on how to debug this would be appreciated.

   TypeError: task is not a function     at /home/work/bluewatertracks/node_modules/async/lib/async.js:689:13     at iterate (/home/work/bluewatertracks/node_modules/async/lib/async.js:265:13)     at async.forEachOfSeries.async.eachOfSeries (/home/work/bluewatertracks/node_modules/async/lib/async.js:284:9)     at _parallel (/home/work/bluewatertracks/node_modules/async/lib/async.js:688:9)     at Object.async.series (/home/work/bluewatertracks/node_modules/async/lib/async.js:710:9)     at Controller.handle (/home/work/bluewatertracks/server/routers/photoUploader.js:56:9)     at Layer.handle [as handle_request] (/home/work/bluewatertracks/node_modules/express/lib/router/layer.js:82:5)     at next (/home/work/bluewatertracks/node_modules/express/lib/router/route.js:110:13)     at Form.<anonymous> (/home/work/bluewatertracks/node_modules/connect-multiparty/index.js:101:9)     at emitNone (events.js:72:20)     at Form.emit (events.js:166:7)     at maybeClose (/home/work/bluewatertracks/node_modules/connect-multiparty/node_modules/multiparty/index.js:557:10)     at endFlush (/home/work/bluewatertracks/node_modules/connect-multiparty/node_modules/multiparty/index.js:552:3)     at WriteStream.<anonymous> (/home/work/bluewatertracks/node_modules/connect-multiparty/node_modules/multiparty/index.js:617:5)     at emitNone (events.js:72:20)     at WriteStream.emit (events.js:166:7) 

回答1:

You can also simplify this a bit by passing a null object to bind():

async.series( [     uploadImage.bind( null, path, destFolder, destination ),     ProcessUpload.bind( null, optionalController, opts, res ) ] ); 

回答2:

async.series and most of the async control flow functions expect functions or arrays of functions to be returned, e.g.

async.series([   function () {},   function () {} ]) 

The return values of your two function calls, uploadImage and ProcessUpload are not functions. async errors out.

Instead you would have to write this as something like:

async.series([     function (callback) {         // callback has to be called by `uploadImage` when it's done         uploadImage(path,destFolder,destination, callback);     }, ]); 

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