source: trip-planner-front/node_modules/svgo/plugins/minifyStyles.js@ 76712b2

Last change on this file since 76712b2 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

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Line 
1'use strict';
2
3/**
4 * @typedef {import('../lib/types').XastElement} XastElement
5 */
6
7const csso = require('csso');
8
9exports.type = 'visitor';
10exports.name = 'minifyStyles';
11exports.active = true;
12exports.description =
13 'minifies styles and removes unused styles based on usage data';
14
15/**
16 * Minifies styles (<style> element + style attribute) using CSSO
17 *
18 * @author strarsis <strarsis@gmail.com>
19 *
20 * @type {import('../lib/types').Plugin<csso.MinifyOptions & Omit<csso.CompressOptions, 'usage'> & {
21 * usage?: boolean | {
22 * force?: boolean,
23 * ids?: boolean,
24 * classes?: boolean,
25 * tags?: boolean
26 * }
27 * }>}
28 */
29exports.fn = (_root, { usage, ...params }) => {
30 let enableTagsUsage = true;
31 let enableIdsUsage = true;
32 let enableClassesUsage = true;
33 // force to use usage data even if it unsafe (document contains <script> or on* attributes)
34 let forceUsageDeoptimized = false;
35 if (typeof usage === 'boolean') {
36 enableTagsUsage = usage;
37 enableIdsUsage = usage;
38 enableClassesUsage = usage;
39 } else if (usage) {
40 enableTagsUsage = usage.tags == null ? true : usage.tags;
41 enableIdsUsage = usage.ids == null ? true : usage.ids;
42 enableClassesUsage = usage.classes == null ? true : usage.classes;
43 forceUsageDeoptimized = usage.force == null ? false : usage.force;
44 }
45 /**
46 * @type {Array<XastElement>}
47 */
48 const styleElements = [];
49 /**
50 * @type {Array<XastElement>}
51 */
52 const elementsWithStyleAttributes = [];
53 let deoptimized = false;
54 /**
55 * @type {Set<string>}
56 */
57 const tagsUsage = new Set();
58 /**
59 * @type {Set<string>}
60 */
61 const idsUsage = new Set();
62 /**
63 * @type {Set<string>}
64 */
65 const classesUsage = new Set();
66
67 return {
68 element: {
69 enter: (node) => {
70 // detect deoptimisations
71 if (node.name === 'script') {
72 deoptimized = true;
73 }
74 for (const name of Object.keys(node.attributes)) {
75 if (name.startsWith('on')) {
76 deoptimized = true;
77 }
78 }
79 // collect tags, ids and classes usage
80 tagsUsage.add(node.name);
81 if (node.attributes.id != null) {
82 idsUsage.add(node.attributes.id);
83 }
84 if (node.attributes.class != null) {
85 for (const className of node.attributes.class.split(/\s+/)) {
86 classesUsage.add(className);
87 }
88 }
89 // collect style elements or elements with style attribute
90 if (node.name === 'style' && node.children.length !== 0) {
91 styleElements.push(node);
92 } else if (node.attributes.style != null) {
93 elementsWithStyleAttributes.push(node);
94 }
95 },
96 },
97
98 root: {
99 exit: () => {
100 /**
101 * @type {csso.Usage}
102 */
103 const cssoUsage = {};
104 if (deoptimized === false || forceUsageDeoptimized === true) {
105 if (enableTagsUsage && tagsUsage.size !== 0) {
106 cssoUsage.tags = Array.from(tagsUsage);
107 }
108 if (enableIdsUsage && idsUsage.size !== 0) {
109 cssoUsage.ids = Array.from(idsUsage);
110 }
111 if (enableClassesUsage && classesUsage.size !== 0) {
112 cssoUsage.classes = Array.from(classesUsage);
113 }
114 }
115 // minify style elements
116 for (const node of styleElements) {
117 if (
118 node.children[0].type === 'text' ||
119 node.children[0].type === 'cdata'
120 ) {
121 const cssText = node.children[0].value;
122 const minified = csso.minify(cssText, {
123 ...params,
124 usage: cssoUsage,
125 }).css;
126 // preserve cdata if necessary
127 // TODO split cdata -> text optimisation into separate plugin
128 if (cssText.indexOf('>') >= 0 || cssText.indexOf('<') >= 0) {
129 node.children[0].type = 'cdata';
130 node.children[0].value = minified;
131 } else {
132 node.children[0].type = 'text';
133 node.children[0].value = minified;
134 }
135 }
136 }
137 // minify style attributes
138 for (const node of elementsWithStyleAttributes) {
139 // style attribute
140 const elemStyle = node.attributes.style;
141 node.attributes.style = csso.minifyBlock(elemStyle, {
142 ...params,
143 }).css;
144 }
145 },
146 },
147 };
148};
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