1 | "use strict";
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2 |
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3 | const is = require("simple-is");
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4 |
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5 | function traverse(root, options) {
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6 | options = options || {};
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7 | const pre = options.pre;
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8 | const post = options.post;
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9 | const cleanup = options.cleanup;
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10 |
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11 | function visit(node, parent) {
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12 | if (!node || !is.string(node.type)) {
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13 | return;
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14 | }
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15 |
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16 | let res = undefined;
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17 | if (pre) {
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18 | res = pre(node, parent);
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19 | }
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20 |
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21 | if (res !== false) {
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22 | for (let prop in node) {
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23 | if (prop[0] === "$") {
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24 | if (cleanup) {
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25 | delete node[prop];
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26 | }
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27 | continue;
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28 | }
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29 |
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30 | const child = node[prop];
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31 |
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32 | if (Array.isArray(child)) {
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33 | for (let i = 0; i < child.length; i++) {
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34 | visit(child[i], node);
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35 | }
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36 | } else {
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37 | visit(child, node);
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38 | }
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39 | }
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40 | }
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41 |
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42 | if (post) {
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43 | post(node, parent);
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44 | }
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45 | }
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46 |
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47 | visit(root, null);
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48 | };
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49 | module.exports = traverse;
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