app.js

'use strict';

var util = require('util');
var async = require('async');

var randomInt = function(low, high) {
  return Math.floor(Math.random() * (high - low) + low);
};

var find = function(key, object, callback) {
  console.log('----------------');
  console.log('In find function');

  async.each(object, function(element, done) {
    console.log('Trying to find key: %s in %s', key, util.inspect(element, {depth: null}));
    if (element.key === key) {
      console.log('Key found!: %s, value: %s', key, element.val);
      done();
      return callback(null, true, element.val);
    }
  }, function(err) {
    if (err) console.log('ERROR ' + err);
    console.log('All elements has been proceeded!');
  });

  console.log('Exiting from find function');
  console.log('--------------------------');
};

var getValue = function(key, obj, callback) {

  // callback(null, 'Not Working!');
  // return;

  var delay = randomInt(300, 1500);
  console.log('Start getVal "' + key + '", delay ' + delay + 'ms');
  setTimeout(function() {
    // Find key there
    find(key, obj, function(err, result, val) {
      if (result) {
        callback(null, val);
      } else {
        console.error(err);
      }
    });
  }, delay);
  console.log('End getVal "' + key + '", delay ' + delay + 'ms');
};

var getKey = function(map, callback) {
  console.log('In getKey function');
  var keys = Object.keys(map);
  async.each(keys, function(key, done) {
    if (typeof key === 'object') getKey(key, callback);
    done();
    return callback(null, key);
  }, function(err) {
    if (err) console.log('Some error!');
    console.log('All keys has been proceed!');
  });
  console.log('Exit getKey function');
};

var transformAsync = function(objects, map, callback) {
  var counter = 0;
  console.log('Function transformAsync is started.');
  console.log('-----------------------------------');
  getKey(map, function(err, key) {
    if (typeof map[key] === 'object') {
      getKey(map[key], function(err, nestedKey) {
        counter++;
        getValue(map[key][nestedKey], objects, function(err, value) {
          map[key][nestedKey] = value;
          if (--counter === 0) callback(null, map);
        });
      });
    } else {
      counter++;
      getValue(map[key], objects, function(err, value) {
        map[key] = value;
        if (--counter === 0) {
          callback(null, map);
        }
      });
    }
  });
  console.log('------------------------');
  console.log('Function async is ended.');
};

transformAsync(require('./data.json'), require('./map.json'), function(err, map) {
  console.log('------ RESULT ------');
  console.log(util.inspect(map, {depth: null}));
  console.log('----- SUCCESS! -----');
});