betfair/lib/betfair_price.js

Betfair JSON API

'use strict';

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

//(C) 2013 Anton Zemlyanov

//This module describes Betfair price
//see Sports API documentation on http://bdp.betfair.com

var epsilon = 0.001;

var BetfairPrice = function () {
    _createClass(BetfairPrice, null, [{
        key: 'price',
        value: function price(_price) {
            return new BetfairPrice(_price);
        }
    }, {
        key: 'increase',
        value: function increase(price) {
            var pr = new BetfairPrice(price);
            return pr.increase();
        }
    }, {
        key: 'decrease',
        value: function decrease(price) {
            var pr = new BetfairPrice(price);
            return pr.decrease();
        }
    }, {
        key: 'spread',
        value: function spread(price1, price2) {
            var pr1 = new BetfairPrice(price1);
            return pr1.spreadToPrice(price2);
        }
    }]);

    function BetfairPrice() {
        var price = arguments.length <= 0 || arguments[0] === undefined ? 1.01 : arguments[0];

        _classCallCheck(this, BetfairPrice);

        this.setPrice(price);
    }

    _createClass(BetfairPrice, [{
        key: 'setPrice',
        value: function setPrice() {
            var price = arguments.length <= 0 || arguments[0] === undefined ? 1.01 : arguments[0];

            if (typeof price === 'string') price = parseFloat(price);

            if (price < 1.01) price = 1.01;else if (price < 2) price = Math.round(price * 100.0) / 100.0;else if (price < 3) price = Math.round(price * 50.0) / 50.0;else if (price < 4) price = Math.round(price * 20.0) / 20.0;else if (price < 6) price = Math.round(price * 10.0) / 10.0;else if (price < 10) price = Math.round(price * 5.0) / 5.0;else if (price < 20) price = Math.round(price * 2.0) / 2.0;else if (price < 30) price = Math.round(price * 1.0) / 1.0;else if (price < 50) price = Math.round(price * 0.5) / 0.5;else if (price < 100) price = Math.round(price * 0.2) / 0.2;else if (price < 1000) price = Math.round(price * 0.1) / 0.1;else price = 1000.0;

            this.price = price.toFixed(2) * 1;
            return;
        }
    }, {
        key: 'increase',
        value: function increase() {
            var price = this.price;

            if (price < 2.0 - epsilon) price += 0.01;else if (price < 3.0 - epsilon) price += 0.02;else if (price < 4.0 - epsilon) price += 0.05;else if (price < 6.0 - epsilon) price += 0.1;else if (price < 10.0 - epsilon) price += 0.2;else if (price < 20.0 - epsilon) price += 0.5;else if (price < 30.0 - epsilon) price += 1.0;else if (price < 50.0 - epsilon) price += 2.0;else if (price < 100.0 - epsilon) price += 5.0;else if (price < 1000.0 - epsilon) price += 10.0;else price = 1000.0;

            this.price = price.toFixed(2) * 1;
            return this;
        }
    }, {
        key: 'decrease',
        value: function decrease() {
            var price = this.price;

            if (price > 100.0 + epsilon) price -= 10.0;else if (price > 50.0 + epsilon) price -= 5.0;else if (price > 30.0 + epsilon) price -= 2.0;else if (price > 20.0 + epsilon) price -= 1.0;else if (price > 10.0 + epsilon) price -= 0.5;else if (price > 6.0 + epsilon) price -= 0.2;else if (price > 4.0 + epsilon) price -= 0.1;else if (price > 3.0 + epsilon) price -= 0.05;else if (price > 2.0 + epsilon) price -= 0.02;else if (price > 1.01 + epsilon) price -= 0.01;else price = 1.01;

            this.price = price.toFixed(2) * 1;
            return this;
        }
    }, {
        key: 'toString',
        value: function toString() {
            var str = this.size.toFixed(2);
            if (str.charAt(str.length - 1) === '0') str = str.substr(0, str.length - 1);
            // if( str.charAt(str.length-1)==='0' )
            // str = str.substr(0, str.length-2);
            return str;
        }
    }, {
        key: 'spreadToPrice',
        value: function spreadToPrice(otherPrice) {
            var other = new BetfairPrice(otherPrice);
            if (Math.abs(this.price - other.price) < epsilon) return 0;
            var spread = 0;
            if (other.price < this.price) {
                // negative spread
                while (other.price < this.price - epsilon) {
                    other.increase();
                    --spread;
                }
            } else {
                // positive spread
                while (other.price > this.price + epsilon) {
                    other.decrease();
                    ++spread;
                }
            }
            return spread;
        }
    }]);

    return BetfairPrice;
}();

module.exports = BetfairPrice;