[6a3a178] | 1 | 'use strict';
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| 2 |
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| 3 | exports.type = 'visitor';
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| 4 | exports.name = 'sortDefsChildren';
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| 5 | exports.active = true;
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| 6 | exports.description = 'Sorts children of <defs> to improve compression';
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| 7 |
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| 8 | /**
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| 9 | * Sorts children of defs in order to improve compression.
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| 10 | * Sorted first by frequency then by element name length then by element name (to ensure grouping).
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| 11 | *
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| 12 | * @author David Leston
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| 13 | *
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| 14 | * @type {import('../lib/types').Plugin<void>}
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| 15 | */
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| 16 | exports.fn = () => {
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| 17 | return {
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| 18 | element: {
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| 19 | enter: (node) => {
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| 20 | if (node.name === 'defs') {
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| 21 | /**
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| 22 | * @type {Map<string, number>}
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| 23 | */
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| 24 | const frequencies = new Map();
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| 25 | for (const child of node.children) {
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| 26 | if (child.type === 'element') {
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| 27 | const frequency = frequencies.get(child.name);
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| 28 | if (frequency == null) {
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| 29 | frequencies.set(child.name, 1);
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| 30 | } else {
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| 31 | frequencies.set(child.name, frequency + 1);
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| 32 | }
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| 33 | }
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| 34 | }
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| 35 | node.children.sort((a, b) => {
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| 36 | if (a.type !== 'element' || b.type !== 'element') {
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| 37 | return 0;
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| 38 | }
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| 39 | const aFrequency = frequencies.get(a.name);
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| 40 | const bFrequency = frequencies.get(b.name);
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| 41 | if (aFrequency != null && bFrequency != null) {
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| 42 | const frequencyComparison = bFrequency - aFrequency;
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| 43 | if (frequencyComparison !== 0) {
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| 44 | return frequencyComparison;
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| 45 | }
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| 46 | }
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| 47 | const lengthComparison = b.name.length - a.name.length;
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| 48 | if (lengthComparison !== 0) {
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| 49 | return lengthComparison;
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| 50 | }
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| 51 | if (a.name !== b.name) {
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| 52 | return a.name > b.name ? -1 : 1;
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| 53 | }
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| 54 | return 0;
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| 55 | });
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| 56 | }
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| 57 | },
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| 58 | },
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| 59 | };
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| 60 | };
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