javascript - Async .eachLimit callback Error not called -

i following code in node.js project.

async.eachlimit(dbresult, 1, function (record, callback) {   var json = json.stringify(record)   var form = new formdata()   form.append('data', json)   form.submit(cfg.server + '/external/api', function (err, res) {     if (err) {      callback(err)     }     if (res.statuscode === 200) {       connection.query('update selected_photos set synced = 1 selected_id = "' + record.selected_id + '"', function (err, result) {         if (err) {           console.log(err)           callback(err)         } else {          callback()         }       })     } else {       console.log(res.statuscode)     return callback(err)     }    }) }, function (err) { // if of file processing produced error, err equal error if (err) {    // 1 of iterations produced error.    // processing stop.    console.log('a share failed process. try rerunning offline sync')      process.exit(0)     } else {       console.log('all files have been processed successfully')       process.exit(0)     }  }) } 

res.statuscode = 302 should error out. the error callback never triggered. how trigger error stops eachlimit , shows the

console.log('a share failed process. try rerunning offline sync') 

you have:

if (err) {

in first line of form submit handler. after that, sure there no error. when check response statuscode , try call error, calling empty value. why not error when checking in final callback function.

try create new error('status not ok: ' + res.statuscode) when calling form submit handler.