traverser.js
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/**
* @fileoverview Wrapper around estraverse
* @author Nicholas C. Zakas
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const estraverse = require("estraverse");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
const KEY_BLACKLIST = [
"parent",
"leadingComments",
"trailingComments"
];
/**
* Wrapper around an estraverse controller that ensures the correct keys
* are visited.
* @constructor
*/
function Traverser() {
const controller = Object.create(new estraverse.Controller()),
originalTraverse = controller.traverse;
// intercept call to traverse() and add the fallback key to the visitor
controller.traverse = function(node, visitor) {
visitor.fallback = Traverser.getKeys;
return originalTraverse.call(this, node, visitor);
};
return controller;
}
/**
* Calculates the keys to use for traversal.
* @param {ASTNode} node The node to read keys from.
* @returns {string[]} An array of keys to visit on the node.
* @private
*/
Traverser.getKeys = function(node) {
return Object.keys(node).filter(key => KEY_BLACKLIST.indexOf(key) === -1);
};
module.exports = Traverser;