55 lines
2.3 KiB
JavaScript
55 lines
2.3 KiB
JavaScript
"use strict";
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// vue compiler module for transforming `img:srcset` to a number of `require`s
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Object.defineProperty(exports, "__esModule", { value: true });
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const utils_1 = require("./utils");
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exports.default = (transformAssetUrlsOptions) => ({
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postTransformNode: (node) => {
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transform(node, transformAssetUrlsOptions);
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}
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});
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// http://w3c.github.io/html/semantics-embedded-content.html#ref-for-image-candidate-string-5
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const escapedSpaceCharacters = /( |\\t|\\n|\\f|\\r)+/g;
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function transform(node, transformAssetUrlsOptions) {
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const tags = ['img', 'source'];
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if (tags.indexOf(node.tag) !== -1 && node.attrs) {
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node.attrs.forEach(attr => {
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if (attr.name === 'srcset') {
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// same logic as in transform-require.js
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const value = attr.value;
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const isStatic = value.charAt(0) === '"' && value.charAt(value.length - 1) === '"';
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if (!isStatic) {
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return;
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}
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const imageCandidates = value
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.substr(1, value.length - 2)
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.split(',')
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.map(s => {
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// The attribute value arrives here with all whitespace, except
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// normal spaces, represented by escape sequences
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const [url, descriptor] = s
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.replace(escapedSpaceCharacters, ' ')
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.trim()
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.split(' ', 2);
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return {
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require: utils_1.urlToRequire(url, transformAssetUrlsOptions),
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descriptor
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};
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});
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// "require(url1)"
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// "require(url1) 1x"
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// "require(url1), require(url2)"
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// "require(url1), require(url2) 2x"
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// "require(url1) 1x, require(url2)"
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// "require(url1) 1x, require(url2) 2x"
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const code = imageCandidates
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.map(({ require, descriptor }) => `${require} + "${descriptor ? ' ' + descriptor : ''}, " + `)
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.join('')
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.slice(0, -6)
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.concat('"')
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.replace(/ \+ ""$/, '');
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attr.value = code;
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}
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});
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}
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}
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