67 lines
1.7 KiB
JavaScript
67 lines
1.7 KiB
JavaScript
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var _ = require('underscore');
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var SOURCE_ID_REGEX = /^([a-z]+)(\d*)$/; // matches a string with one or more letters + numbers, e.g. 'b2'
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var newId = function (id, seqChange) {
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if (!id || !id.match) throw new Error('invalid id');
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var matches = id.match(SOURCE_ID_REGEX);
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matches[2] = matches[2] || -1;
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if (matches && matches.length === 3) {
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// letter + next number
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var letter = matches[1];
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var seq = parseInt(matches[2], 10) + seqChange;
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return letter + Math.max(seq, 0);
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} else {
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throw new Error('invalid id');
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}
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};
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/**
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* Encapsulates logic related to the nodes' IDs.
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*/
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module.exports = {
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/**
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* Get next id in sequence of given source id.
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* @param {String} id, e.g. 'c2'
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* @return {String} e.g. 'c3'
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*/
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next: function (id) {
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return newId(id, 1);
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},
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prev: function (id) {
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return newId(id, -1);
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},
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/**
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* Get the letter representation.
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* @param {String, Object} sourceId or backbone model that have id. e.g. 'c2'
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* @return {String} e.g. 'c' or an empty string if there is no letter in the given id
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*/
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letter: function (sourceId) {
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if (!sourceId || !_.isString(sourceId)) return '';
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var match = sourceId.match(/^([a-z]+)/);
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return _.isArray(match) && match[0] || '';
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},
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/**
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* Get the sequence representation.
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* @param {String, Object} sourceId or backbone model that have id. e.g. 'c2'
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* @return {Number} e.g. 2 or undefined if there is no sequence
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*/
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sequence: function (sourceId) {
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if (!sourceId || !_.isString(sourceId)) return;
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var match = sourceId.match(/(\d+$)/);
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return _.isArray(match) && match[0] || undefined;
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},
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changeLetter: function (id, newLetter) {
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var seq = id.match(/(\d+)$/)[0];
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return newLetter + seq;
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}
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};
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