40 lines
1.2 KiB
JavaScript
40 lines
1.2 KiB
JavaScript
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'use strict';
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var postcss = require('postcss');
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module.exports = postcss.plugin('postcss-zindex', function (opts) {
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opts = opts || {};
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return function (css) {
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var cache = require('./lib/layerCache')(opts);
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var nodes = [];
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var abort = false;
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// First pass; cache all z indexes
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css.walkDecls('z-index', function (decl) {
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// Check that no negative values exist. Rebasing is only
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// safe if all indices are positive numbers.
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if (decl.value[0] === '-') {
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abort = true;
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// Stop PostCSS iterating through the rest of the decls
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return false;
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}
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nodes.push(decl);
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cache.addValue(decl.value);
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});
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// Abort if we found any negative values
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// or there are no z-index declarations
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if (abort || !nodes.length) {
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return;
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}
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cache.optimizeValues();
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// Second pass; optimize
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nodes.forEach(function (decl) {
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// Need to coerce to string so that the
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// AST is updated correctly
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decl.value = cache.getValue(decl.value).toString();
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});
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};
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});
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