'use strict';
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exports.type = 'perItem';
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exports.active = true;
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exports.description = 'Sorts children of <defs> to improve compression';
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/**
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* Sorts children of defs in order to improve compression.
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* Sorted first by frequency then by element name length then by element name (to ensure grouping).
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*
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* @param {Object} item current iteration item
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* @return {Boolean} if false, item will be filtered out
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*
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* @author David Leston
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*/
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exports.fn = function(item) {
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if (item.isElem('defs')) {
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if (item.content) {
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var frequency = item.content.reduce(function (frequency, child) {
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if (child.elem in frequency) {
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frequency[child.elem]++;
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} else {
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frequency[child.elem] = 1;
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}
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return frequency;
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}, {});
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item.content.sort(function (a, b) {
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var frequencyComparison = frequency[b.elem] - frequency[a.elem];
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if (frequencyComparison !== 0 ) {
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return frequencyComparison;
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}
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var lengthComparison = b.elem.length - a.elem.length;
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if (lengthComparison !== 0) {
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return lengthComparison;
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}
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return a.elem != b.elem ? a.elem > b.elem ? -1 : 1 : 0;
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});
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}
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return true;
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}
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};
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