69 lines
1.5 KiB
JavaScript
69 lines
1.5 KiB
JavaScript
var VISITOR_KEYS = require("./visitor-keys");
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var _ = require("lodash");
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var traverse = module.exports = function (parent, callback) {
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if (_.isArray(parent)) {
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_.each(parent, function (node) {
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traverse(node, callback);
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});
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return;
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}
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var keys = VISITOR_KEYS[parent.type] || [];
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_.each(keys, function (key) {
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var nodes = parent[key];
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if (!nodes) return;
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var handle = function (obj, key) {
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if (!obj[key]) return;
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// strict references in case the callback modified/replaced the node
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var result = callback(obj[key], parent, obj, key);
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if (result === false) return;
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traverse(obj[key], callback);
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};
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if (_.isArray(nodes)) {
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_.each(nodes, function (node, i) {
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handle(nodes, i);
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});
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parent[key] = _.flatten(nodes).filter(function (node) {
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return node !== traverse.Delete;
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});
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} else {
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handle(parent, key);
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}
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});
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};
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traverse.Delete = {};
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traverse.hasType = function (tree, type) {
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var has = false;
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if (_.isArray(tree)) {
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return !!_.find(tree, function (node) {
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return traverse.hasType(node, type);
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});
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} else {
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traverse(tree, function (node) {
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if (node.type === type) {
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has = true;
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return false;
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}
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});
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}
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return has;
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};
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traverse.replace = function (node, callback) {
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traverse(node, function (node, parent, obj, key) {
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var result = callback(node, parent);
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if (result != null) obj[key] = result;
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});
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};
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