built.io-browserify/lib/location.js

SDK for Built.io Backend which is compatible with Browserify

var R                     = require('ramda');
var utility               = require('./utilities/utility');
var instanceMethodBuilder = require('./utilities/instanceMethodBuilder')();
var when                  = require('when');

/**
* @class Location
* @classdesc
*   Location represents a geological location.
* @instance
* @description 
*   Use this to get a location instance.
* @param {Number} longitude Longitutde value
* @param {Number} latitude Latitude value 
* @throws new Error("Longitutde should be in the range of -180 to 180");
* @throws new Error("Latitude should be in the range of -90 to 90");
* @throws new TypeError("Invalide data type");
* @example
* var location = Built.Location(60,80);
* @return {Location}
*/
var locCons = module.exports = function(longitude,latitude) {
	var data  = {};
	if(longitude && latitude)
		locationValidator(longitude,latitude);
	data.longitude  = longitude;
	data.latitude   = latitude;
	var returnObj   = {
		toJSON:function(){
			return data;
		},
		data: data
	}
	return instanceMethodBuilder.build(module.exports,returnObj);
}

/**
* Sets the location with given values
* @function setLocation
* @param {Number} longitude Longitutde value
* @param {Number} latitude Latitude value
* @throws new Error("Longitutde should be in the range of -180 to 180");
* @throws new Error("Latitude should be in the range of -90 to 90");
* @throws new TypeError("Invalide data type");
* @instance
* @memberof Location
* @example 
* var location = Built.Location();
* location = location.setLocation(60,80);
* @return {Location}
*/
module.exports.setLocation = R.curry(function(longitude,latitude,loc){
	return locCons(longitude,latitude);
});
instanceMethodBuilder.define('setLocation',3);
/**
* Gets your current location
* @function getCurrentLocation
* @static
* @memberof Location
* @example
* Location.getCurrentLocation()
* .then(function(location){
*    console.log(location)
* });
* @return {Promise<Location>}
*/
module.exports.getCurrentLocation = function(){
	var deferred = when.defer();
	if(typeof navigator!=='undefined' && typeof navigator.geolocation !=='undefined'){
		navigator.geolocation.getCurrentPosition(function(location) {
			return deferred.resolve(locCons(location.coords.longitude,location.coords.latitude));
		},
		function(error){
			deferred.reject(error);
		})
	}
	return deferred.promise;
};
/**
* Gets the distance between this location to another location in kilometers
* @function kilometersFrom
* @param {Location} anotherLocation Location instance
* @instance
* @memberof Location
* @example 
* var point1 = Location(100,90);
* var point2 = Location(100,80);
* var result = point1.kilometersFrom(point2);
* @return {Number}
*/
module.exports.kilometersFrom = function(anotherLoc,loc){
	var anotherData = anotherLoc.toJSON();
	var curData     = loc.toJSON();
	return haversine(curData.longitude,curData.latitude,anotherData.longitude,anotherData.latitude,1);
}
instanceMethodBuilder.define('kilometersFrom',2);
/**
* Gets the distance between this location to another location in meters
* @function metersFrom
* @param {Location} anotherLocation Location instance
* @instance
* @memberof Location
* @example 
* var point1 = Location(100,90);
* var point2 = Location(100,80);
* var result = point1.metersFrom(point2);
* @return {Number}
*/
module.exports.metersFrom= function(anotherLoc,loc){
	var anotherData = anotherLoc.toJSON();
	var curData     = loc.toJSON();
	return haversine(curData.longitude,curData.latitude,anotherData.longitude,anotherData.latitude,1000);
}
instanceMethodBuilder.define('metersFrom',2);
/**
* Gets the distance between this location to another location in miles
* @function milesFrom
* @param {Location} anotherLocation Location instance
* @instance
* @memberof Location
* @example 
* var point1 = Location(100,90);
* var point2 = Location(100,80);
* var result = point1.milesFrom(point2);
* @return {Number}
*/
module.exports.milesFrom= function(anotherLoc,loc){
	var anotherData = anotherLoc.toJSON();
	var curData     = loc.toJSON();
	return haversine(curData.longitude,curData.latitude,anotherData.longitude,anotherData.latitude,0.621371);
}
instanceMethodBuilder.define('milesFrom',2);

function locationValidator(longitude,latitude){
	if(typeof longitude != 'number' || typeof latitude != 'number'){
		throw new TypeError("Invalid data type");
	}
	if (longitude < -180.0 ||longitude > 180.0) {
		throw new Error("Longitutde should be in the range of -180 to 180");
	}
	if (latitude < -90.0 || latitude > 90.0) {
		throw new Error("Latitude should be in the range of -90 to 90");
	}
}

function haversine(long1,lat1,long2,lat2,factor){
	var pi     = Math.PI / 180.0;
	var range  = 6378.1 * factor;

	var rlat1  = lat1  * pi; 
	var rlong1 = long1 * pi; 
	var rlat2  = lat2  * pi; 
	var rlong2 = long2 * pi;

	var dlon   = rlong1 - rlong2;
	var dlat   = rlat1  - rlat2;

	var a      = Math.pow(Math.sin(dlat/2),2) + Math.cos(rlat1) * Math.cos(rlat2) * Math.pow(Math.sin(dlon/2), 2);
	var c      = 2 * Math.atan2(Math.sqrt(a),Math.sqrt(1-a));
	var d      = range * c;
	return Math.ceil(d);
}