[INTERNAL] Use Object.create(null) for dynamic maps

Author: matz3

lib/ReaderCollectionPrioritized.js

@@ -37,7 +37,7 @@ class ReaderCollectionPrioritized extends AbstractReader {
 		return Promise.all(this._readers.map(function(resourceLocator) {
 			return resourceLocator._byGlob(pattern, options, trace);
 		})).then((result) => {
-			const files = {};
+			const files = Object.create(null);
 			const resources = [];
 			// Prefer files found in preceding resource locators
 			for (let i = 0; i < result.length; i++) {

lib/Resource.js

@@ -368,12 +368,12 @@ class Resource {
 	 * @returns {object} Trace tree
 	 */
 	getPathTree() {
-		const tree = {};
+		const tree = Object.create(null);
 
-		let pointer = tree[this._path] = {};
+		let pointer = tree[this._path] = Object.create(null);
 
 		for (let i = this._collections.length - 1; i >= 0; i--) {
-			pointer = pointer[this._collections[i]] = {};
+			pointer = pointer[this._collections[i]] = Object.create(null);
 		}
 
 		return tree;

lib/ResourceTagCollection.js

@@ -29,7 +29,7 @@ class ResourceTagCollection {
 			this._allowedNamespacesRegExp = null;
 		}
 
-		this._pathTags = tags || {};
+		this._pathTags = tags || Object.create(null);
 	}
 
 	setTag(resourcePath, tag, value = true) {
@@ -38,7 +38,7 @@ class ResourceTagCollection {
 		this._validateValue(value);
 
 		if (!this._pathTags[resourcePath]) {
-			this._pathTags[resourcePath] = {};
+			this._pathTags[resourcePath] = Object.create(null);
 		}
 		this._pathTags[resourcePath][tag] = value;
 	}

lib/adapters/Memory.js

@@ -23,8 +23,8 @@ class Memory extends AbstractAdapter {
 	 */
 	constructor({virBasePath, project, excludes}) {
 		super({virBasePath, project, excludes});
-		this._virFiles = {}; // map full of files
-		this._virDirs = {}; // map full of directories
+		this._virFiles = Object.create(null); // map full of files
+		this._virDirs = Object.create(null); // map full of directories
 	}
 
 	/**

lib/tracing/Trace.js

@@ -21,7 +21,7 @@ class Trace {
 		this._startTime = process.hrtime();
 		this._globCalls = 0;
 		this._pathCalls = 0;
-		this._collections = {};
+		this._collections = Object.create(null);
 		summaryTrace.traceStarted();
 	}