426 lines
No EOL
12 KiB
JavaScript
426 lines
No EOL
12 KiB
JavaScript
/**
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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 _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
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function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
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var DEFAULT_COLLECTION_PROP = 'expressions';
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var DEFAULT_SINGLE_PROP = 'expression';
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/**
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* NodePath class encapsulates a traversing node,
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* its parent node, property name in the parent node, and
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* an index (in case if a node is part of a collection).
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* It also provides set of methods for AST manipulation.
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*/
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var NodePath = function () {
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/**
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* NodePath constructor.
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*
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* @param Object node - an AST node
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* @param NodePath parentPath - a nullable parent path
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* @param string property - property name of the node in the parent
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* @param number index - index of the node in a collection.
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*/
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function NodePath(node) {
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var parentPath = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;
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var property = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;
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var index = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : null;
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_classCallCheck(this, NodePath);
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this.node = node;
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this.parentPath = parentPath;
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this.parent = parentPath ? parentPath.node : null;
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this.property = property;
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this.index = index;
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}
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_createClass(NodePath, [{
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key: '_enforceProp',
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value: function _enforceProp(property) {
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if (!this.node.hasOwnProperty(property)) {
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throw new Error('Node of type ' + this.node.type + ' doesn\'t have "' + property + '" collection.');
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}
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}
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/**
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* Sets a node into a children collection or the single child.
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* By default child nodes are supposed to be under `expressions` property.
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* An explicit property can be passed.
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*
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* @param Object node - a node to set into a collection or as single child
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* @param number index - index at which to set
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* @param string property - name of the collection or single property
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*/
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}, {
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key: 'setChild',
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value: function setChild(node) {
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var index = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;
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var property = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;
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var childPath = void 0;
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if (index != null) {
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if (!property) {
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property = DEFAULT_COLLECTION_PROP;
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}
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this._enforceProp(property);
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this.node[property][index] = node;
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childPath = NodePath.getForNode(node, this, property, index);
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} else {
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if (!property) {
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property = DEFAULT_SINGLE_PROP;
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}
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this._enforceProp(property);
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this.node[property] = node;
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childPath = NodePath.getForNode(node, this, property, null);
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}
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return childPath;
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}
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/**
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* Appends a node to a children collection.
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* By default child nodes are supposed to be under `expressions` property.
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* An explicit property can be passed.
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*
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* @param Object node - a node to set into a collection or as single child
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* @param string property - name of the collection or single property
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*/
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}, {
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key: 'appendChild',
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value: function appendChild(node) {
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var property = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;
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if (!property) {
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property = DEFAULT_COLLECTION_PROP;
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}
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this._enforceProp(property);
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var end = this.node[property].length;
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return this.setChild(node, end, property);
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}
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/**
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* Inserts a node into a collection.
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* By default child nodes are supposed to be under `expressions` property.
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* An explicit property can be passed.
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*
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* @param Object node - a node to insert into a collection
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* @param number index - index at which to insert
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* @param string property - name of the collection property
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*/
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}, {
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key: 'insertChildAt',
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value: function insertChildAt(node, index) {
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var property = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : DEFAULT_COLLECTION_PROP;
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this._enforceProp(property);
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this.node[property].splice(index, 0, node);
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// If we inserted a node before the traversing index,
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// we should increase the later.
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if (index <= NodePath.getTraversingIndex()) {
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NodePath.updateTraversingIndex(+1);
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}
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this._rebuildIndex(this.node, property);
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}
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/**
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* Removes a node.
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*/
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}, {
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key: 'remove',
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value: function remove() {
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if (this.isRemoved()) {
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return;
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}
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NodePath.registry.delete(this.node);
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this.node = null;
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if (!this.parent) {
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return;
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}
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// A node is in a collection.
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if (this.index !== null) {
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this.parent[this.property].splice(this.index, 1);
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// If we remove a node before the traversing index,
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// we should increase the later.
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if (this.index <= NodePath.getTraversingIndex()) {
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NodePath.updateTraversingIndex(-1);
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}
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// Rebuild index.
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this._rebuildIndex(this.parent, this.property);
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this.index = null;
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this.property = null;
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return;
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}
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// A simple node.
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delete this.parent[this.property];
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this.property = null;
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}
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/**
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* Rebuilds child nodes index (used on remove/insert).
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*/
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}, {
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key: '_rebuildIndex',
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value: function _rebuildIndex(parent, property) {
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var parentPath = NodePath.getForNode(parent);
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for (var i = 0; i < parent[property].length; i++) {
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var path = NodePath.getForNode(parent[property][i], parentPath, property, i);
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path.index = i;
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}
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}
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/**
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* Whether the path was removed.
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*/
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}, {
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key: 'isRemoved',
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value: function isRemoved() {
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return this.node === null;
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}
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/**
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* Replaces a node with the passed one.
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*/
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}, {
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key: 'replace',
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value: function replace(newNode) {
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NodePath.registry.delete(this.node);
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this.node = newNode;
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if (!this.parent) {
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return null;
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}
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// A node is in a collection.
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if (this.index !== null) {
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this.parent[this.property][this.index] = newNode;
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}
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// A simple node.
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else {
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this.parent[this.property] = newNode;
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}
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// Rebuild the node path for the new node.
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return NodePath.getForNode(newNode, this.parentPath, this.property, this.index);
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}
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/**
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* Updates a node inline.
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*/
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}, {
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key: 'update',
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value: function update(nodeProps) {
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Object.assign(this.node, nodeProps);
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}
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/**
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* Returns parent.
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*/
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}, {
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key: 'getParent',
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value: function getParent() {
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return this.parentPath;
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}
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/**
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* Returns nth child.
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*/
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}, {
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key: 'getChild',
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value: function getChild() {
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var n = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
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if (this.node.expressions) {
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return NodePath.getForNode(this.node.expressions[n], this, DEFAULT_COLLECTION_PROP, n);
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} else if (this.node.expression && n == 0) {
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return NodePath.getForNode(this.node.expression, this, DEFAULT_SINGLE_PROP);
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}
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return null;
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}
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/**
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* Whether a path node is syntactically equal to the passed one.
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*
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* NOTE: we don't rely on `source` property from the `loc` data
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* (which would be the fastest comparison), since it might be unsync
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* after several modifications. We use here simple `JSON.stringify`
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* excluding the `loc` data.
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*
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* @param NodePath other - path to compare to.
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* @return boolean
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*/
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}, {
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key: 'hasEqualSource',
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value: function hasEqualSource(path) {
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return JSON.stringify(this.node, jsonSkipLoc) === JSON.stringify(path.node, jsonSkipLoc);
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}
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/**
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* JSON-encodes a node skipping location.
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*/
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}, {
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key: 'jsonEncode',
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value: function jsonEncode() {
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var _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
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format = _ref.format,
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useLoc = _ref.useLoc;
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return JSON.stringify(this.node, useLoc ? null : jsonSkipLoc, format);
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}
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/**
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* Returns previous sibling.
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*/
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}, {
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key: 'getPreviousSibling',
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value: function getPreviousSibling() {
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if (!this.parent || this.index == null) {
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return null;
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}
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return NodePath.getForNode(this.parent[this.property][this.index - 1], NodePath.getForNode(this.parent), this.property, this.index - 1);
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}
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/**
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* Returns next sibling.
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*/
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}, {
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key: 'getNextSibling',
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value: function getNextSibling() {
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if (!this.parent || this.index == null) {
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return null;
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}
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return NodePath.getForNode(this.parent[this.property][this.index + 1], NodePath.getForNode(this.parent), this.property, this.index + 1);
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}
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/**
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* Returns a NodePath instance for a node.
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*
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* The same NodePath can be reused in several places, e.g.
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* a parent node passed for all its children.
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*/
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}], [{
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key: 'getForNode',
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value: function getForNode(node) {
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var parentPath = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;
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var prop = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;
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var index = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : -1;
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if (!node) {
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return null;
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}
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if (!NodePath.registry.has(node)) {
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NodePath.registry.set(node, new NodePath(node, parentPath, prop, index == -1 ? null : index));
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}
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var path = NodePath.registry.get(node);
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if (parentPath !== null) {
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path.parentPath = parentPath;
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path.parent = path.parentPath.node;
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}
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if (prop !== null) {
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path.property = prop;
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}
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if (index >= 0) {
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path.index = index;
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}
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return path;
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}
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/**
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* Initializes the NodePath registry. The registry is a map from
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* a node to its NodePath instance.
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*/
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}, {
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key: 'initRegistry',
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value: function initRegistry() {
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if (!NodePath.registry) {
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NodePath.registry = new Map();
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}
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NodePath.registry.clear();
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}
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/**
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* Updates index of a currently traversing collection.
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*/
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}, {
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key: 'updateTraversingIndex',
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value: function updateTraversingIndex(dx) {
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return NodePath.traversingIndexStack[NodePath.traversingIndexStack.length - 1] += dx;
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}
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/**
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* Returns current traversing index.
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*/
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}, {
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key: 'getTraversingIndex',
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value: function getTraversingIndex() {
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return NodePath.traversingIndexStack[NodePath.traversingIndexStack.length - 1];
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}
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}]);
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return NodePath;
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}();
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NodePath.initRegistry();
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/**
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* Index of a currently traversing collection is stored on top of the
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* `NodePath.traversingIndexStack`. Remove/insert methods can adjust
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* this index.
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*/
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NodePath.traversingIndexStack = [];
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// Helper function used to skip `loc` in JSON operations.
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function jsonSkipLoc(prop, value) {
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if (prop === 'loc') {
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return undefined;
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}
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return value;
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}
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module.exports = NodePath; |