fly-js/src/helpers/scales/Beaufort.js

A JavaScript utility library focusing on aviation

/*jslint node: true */
"use strict";

var _ = require('lodash');

var Beaufort = function () {

    this.scale = [
        {
            "force": 0,
            "description": "Calm",
            "windspeed": {
                "lower": 0,
                "upper": 0
            }
        },
        {
            "force": 1,
            "description": "Light Air",
            "windspeed": {
                "lower": 1,
                "upper": 3
            }
        },
        {
            "force": 2,
            "description": "Light Breeze",
            "windspeed": {
                "lower": 4,
                "upper": 6
            }
        },
        {
            "force": 3,
            "description": "Gentle Breeze",
            "windspeed": {
                "lower": 7,
                "upper": 10
            }
        },
        {
            "force": 4,
            "description": "Moderate Breeze",
            "windspeed": {
                "lower": 11,
                "upper": 16
            }
        },
        {
            "force": 5,
            "description": "Fresh Breeze",
            "windspeed": {
                "lower": 17,
                "upper": 21
            }
        },
        {
            "force": 6,
            "description": "Strong Breeze",
            "windspeed": {
                "lower": 22,
                "upper": 27
            }
        },
        {
            "force": 7,
            "description": "Near Gale",
            "windspeed": {
                "lower": 28,
                "upper": 33
            }
        },
        {
            "force": 8,
            "description": "Fresh Gale",
            "windspeed": {
                "lower": 34,
                "upper": 40
            }
        },
        {
            "force": 9,
            "description": "Strong Gale",
            "windspeed": {
                "lower": 41,
                "upper": 47
            }
        },
        {
            "force": 10,
            "description": "Storm",
            "windspeed": {
                "lower": 48,
                "upper": 55
            }
        },
        {
            "force": 11,
            "description": "Violent Storm",
            "windspeed": {
                "lower": 56,
                "upper": 63 
            }
        },
        {
            "force": 12,
            "description": "Hurricane",
            "windspeed": {
                "lower": 64,
                "upper": Infinity 
            }
        }
    ];

};

Beaufort.prototype.between = function (item, windKnotes) {
    return windKnotes >= item.windspeed.lower && windKnotes <= item.windspeed.upper;
};

Beaufort.prototype.lookup = function (windKnotes, key) {

    var match = null;

    if (!key) {
        key = "description";
    }

    _.forOwn(this.scale, function (item) {

        if (this.between(item, windKnotes)) {
            match = item[key] || item;
        }
    }, this);

    return match;
};

module.exports = new Beaufort();