geo-distances/index.js

A geographical distance calculator. Calculates distance between two points using haversine formula.

'use strict'

let lib = require('./lib'),
    colors = require('colors'),
    distances = [],
    message = ' cannot be empty';


    /**
    * Return distance between two co-ordinates point
    * 
    * @param {String} filepath filepath in string
    * @param {Object} start starting point coordinate
    * @param {String} range of distances
    * @param {unit} unit unit of distance measurement
    * @returns {Object}
    */


let getDistances = (filepath, start, range, unit) => {

    let data = require(filepath), lat1 = start.latitude, lon1 = start.longitude;

    let log = ((index, type, message) => {
        if (type == 'error') {
            console.log(colors.red(`error: In data array ${index} object is empty`))
            console.log(colors.red(`${type}: ${message}`));
            process.exit()
        }
    })

    /**
    * Check if Latitude or Longitude is empty or undefined
    * 
    * @param {Number} index index of object in array
    * @param {String} type error or success
    * @param {Object} coordinate location coordinate
    * @returns {Object}
    */

    let checkCoordinates = ((index, type, coordinate) => {
        if (coordinate.trim() === "" || coordinate === undefined) {
            log(index, 'error', type + message);
        }
        return coordinate;
    })

    data.filter((obj, index) => {
        let lat2 = checkCoordinates( index, 'latitude', obj.latitude);
        let lon2 = checkCoordinates(index, 'longitude', obj.longitude);
        let distance = lib.distance(lat1, lon1, lat2, lon2, unit);
        if (distance <= range) {
            obj["distance"] = distance
            distances.push(obj);
        }
    });

    return distances;

}

module.exports = getDistances;