44 lines
1.0 KiB
JavaScript
44 lines
1.0 KiB
JavaScript
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/**
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* The MIT License (MIT)
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* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
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*/
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'use strict';
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var NodePath = require('../../traverse/node-path');
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var _require = require('../../transform/utils'),
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disjunctionToList = _require.disjunctionToList,
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listToDisjunction = _require.listToDisjunction;
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/**
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* Removes duplicates from a disjunction sequence:
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*
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* /(ab|bc|ab)+(xy|xy)+/ -> /(ab|bc)+(xy)+/
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*/
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module.exports = {
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Disjunction: function Disjunction(path) {
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var node = path.node;
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// Make unique nodes.
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var uniqueNodesMap = {};
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var parts = disjunctionToList(node).filter(function (part) {
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var encoded = part ? NodePath.getForNode(part).jsonEncode() : 'null';
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// Already recorded this part, filter out.
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if (uniqueNodesMap.hasOwnProperty(encoded)) {
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return false;
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}
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uniqueNodesMap[encoded] = part;
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return true;
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});
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// Replace with the optimized disjunction.
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path.replace(listToDisjunction(parts));
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}
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};
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