nd-cust-geo/index.js

We have some customer records in a text file (customers.txt) -- one customer per line, JSON lines formatted. We want to invite any customer within 100km of Dublin for some food and drinks on us. Write a program that will read the full list of customers an

var fs = require('fs');
var readline = require('readline');

module.exports = {
 custParams : {
   'lat': 'ORIGIN-LATITUDE',
   'lon': 'ORIGIN-LONGITUDE',
   'fileDest': 'CUSTOMERS-FILE-PATH',
   'range':'FILTER-RANGE-KM',
   'sortBy':'SORT-KEY'
  },

  setCustParams: function(lat, lon, fileDest,range,sort) {
    this.custParams.lat = lat;
    this.custParams.lon = lon;
    this.custParams.fileDest = fileDest;
    this.custParams.range = range;
    this.custParams.sortBy=sort;
  },
  getcustomers: async function(sortByKey){
        
    try{
      if(this.custParams.lat=="" || this.custParams.lat==undefined){
        throw new SyntaxError("Origin latitude is not found.");
      }
      if(this.custParams.lon=="" || this.custParams.lon==undefined){
        throw new SyntaxError("Origin longitude is not found.");
      }
      if(this.custParams.fileDest=="" || this.custParams.fileDest==undefined){
        throw new SyntaxError("File path is not found.");
      }
      if(this.custParams.range=="" || this.custParams.range==undefined){
        throw new SyntaxError("Range is not found.");
      }

      if(this.custParams.sortBy=="" || this.custParams.sortBy==undefined){
        throw new SyntaxError("sortBy key not found.");
      }

    }catch(e){
      console.log( "Error: " + e.message );
      return false;
    }

     return this.sortByKey(await this.getcustomersTxt(this),this.custParams.sortBy);
 
 
    },

  getcustomersTxt: function(params){
    
  var customersArray =[];
   return new Promise(function(res,rej){
        var stats = fs.stat(params.custParams.fileDest, function(err,stat){
          try{ 
              if (!err) {
                  let readInterface = readline.createInterface({input: fs.createReadStream(params.custParams.fileDest)});
                  readInterface.on('line', function(line) {
                    let jsonObj  = JSON.parse(line);
                   
                    // get user distance 
                    let dist  = params.distance(params.custParams.lat, params.custParams.lon, jsonObj.latitude, jsonObj.longitude, 'K');
                    if(dist<params.custParams.range){
                        customersArray.push(jsonObj);
                    }
                  }).on('close', function() {
                     res(customersArray); 
                    }).on('error', function (e) {
                      throw new SyntaxError(e); 
                    });
                }else{
                   throw new SyntaxError("File not found as you provided path.");
               }
            }catch(e){
              if(e.name == "SyntaxError") {
                console.log( "Error: " + e.message );
              } else {
                throw e; 
              }
           }
        }); 
  });
},
distance:function(lat1, lon1, lat2, lon2, unit){
	if ((lat1 == lat2) && (lon1 == lon2)) {
		return 0;
	}
	else {
		var radlat1 = Math.PI * lat1/180;   //convert Degrees to Radians 
		var radlat2 = Math.PI * lat2/180;   //convert Degrees to Radians 
		var theta = lon1-lon2;
		var radtheta = Math.PI * theta/180;
		var dist = Math.sin(radlat1) * Math.sin(radlat2) + Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta);
		if (dist > 1) {
			dist = 1;
		}
		dist = Math.acos(dist);
		dist = dist * 180/Math.PI;
		dist = dist * 60 * 1.1515;
		if (unit=="K") { dist = dist * 1.609344 }
		if (unit=="N") { dist = dist * 0.8684 }
		return dist.toFixed(2);
	}
},
sortByKey:function(array, key) {
  return array.sort(function(a, b) {
      var x = a[key]; var y = b[key];
      return ((x < y) ? -1 : ((x > y) ? 1 : 0));
  });
}
};