49 lines
1.3 KiB
JavaScript
49 lines
1.3 KiB
JavaScript
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var _ = require('underscore');
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/**
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* Value object to calcualte distances
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*/
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module.exports = {
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OPTIONS: [
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{
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distance: 'meters',
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metersPerDistance: 1
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}, {
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distance: 'kilometers',
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metersPerDistance: 1000
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}, {
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distance: 'miles',
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metersPerDistance: 1609.34
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}
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],
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/**
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* @param {Number} val - e.g. 3
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* @param {String} distance - e.g. 'kilometers'
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* @param {Float} e.g. 3000
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*/
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toMeters: function (val, distance) {
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val = parseFloat(val);
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if (isNaN(val)) throw new Error('val (1st arg) is required, expected a parseable number or float');
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var option = _.find(this.OPTIONS, function (d) {
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return d.distance === distance;
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});
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if (!option) throw new Error(distance + ' (2nd arg) is not a valid distance value, expects one of ' + _.pluck(this.OPTIONS, 'distance').join(', '));
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return val * option.metersPerDistance;
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},
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toDistance: function (meters, distance) {
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meters = parseFloat(meters);
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if (isNaN(meters)) throw new Error('meters (1st arg) is required');
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var option = _.find(this.OPTIONS, function (d) {
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return d.distance === distance;
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});
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if (!option) throw new Error(distance + ' (2nd arg) is not a valid distance value, expects one of ' + _.pluck(this.OPTIONS, 'distance').join(', '));
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return meters / option.metersPerDistance;
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}
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};
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