javascript - Iterate over array in async promise -

i´m working node/ express, mysql , bluebird.

i´m using promises make async database call, working far. want iterate on result (array) , call function calculation purpose.

my code separated controller class, handles get/ post request. in middle service class business logic, talks database class queries in database.

for show service class, because else working perfectly, don´t know how run on result array , call function, returns daterange.

'use strict';  var departmentdatabase = require('../database/department'); var moment = require('moment');  class departmentservice {     constructor() {     }      getvacation(departmentid) {         return departmentdatabase.getvacation(departmentid).then(function (result) {              //without promises did this, worked.             //for(var = 0; result.length > i; i++){             // var daterange = this.getdaterange(new date(result[i].datefrom), new date(result[i].dateto));             //console.log(daterange);             //}             return result;          })          //if static, daterange function called         //but here don´t know how entire array.         //also don´t know, how correctly result daterange()         .then(result => this.daterange(result[0].datefrom, result[0].dateto))         //.then() here need array of dateranges         .catch(function (err) {             console.log(err);         });     }      getdaterange(startdate, stopdate) {         console.log("indaterange");         console.log(startdate + stopdate);          var datearray = [];         var currentdate = moment(startdate);         while (currentdate <= stopdate) {             datearray.push(moment(currentdate).format('yyyy-mm-dd'))             currentdate = moment(currentdate).add(1, 'days');         }          return datearray;     } }  module.exports = new departmentservice(); 

hope can give me example on how right.

in new code, you're handling first result. want map:

.then(result => result.map(entry => this.daterange(entry.datefrom, entry.dateto))) 

so in context old code removed:

getvacation(departmentid) {     return departmentdatabase.getvacation(departmentid)     .then(result => result.map(entry => this.daterange(entry.datefrom, entry.dateto)))     .catch(function (err) {         console.log(err);         // warning - `catch` handler converts failure         //           resolution value `undefined`!     }); } 

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note warning in above. if want propagate error, need explicitly:

.catch(err => {     // ...do it...     // if want propagate it:     return promise.reject(err);     // or can do:     // throw err; });