Merge pull request #212 from haggholm/es6-collection-lookups

fix(perf): Use ES6 collections for lookups in crawl().

Author: Phil Sturgeon

lib/dereference.js

@@ -16,7 +16,7 @@ module.exports = dereference;
  */
 function dereference (parser, options) {
  // console.log('Dereferencing $ref pointers in %s', parser.$refs._root$Ref.path);
- let dereferenced = crawl(parser.schema, parser.$refs._root$Ref.path, "#", [], [], {}, parser.$refs, options);
+ let dereferenced = crawl(parser.schema, parser.$refs._root$Ref.path, "#", new Set(), new Set(), new Map(), parser.$refs, options);
  parser.$refs.circular = dereferenced.circular;
  parser.schema = dereferenced.value;
 }
@@ -27,9 +27,9 @@ function dereference (parser, options) {
  * @param {*} obj - The value to crawl. If it's not an object or array, it will be ignored.
  * @param {string} path - The full path of `obj`, possibly with a JSON Pointer in the hash
  * @param {string} pathFromRoot - The path of `obj` from the schema root
- * @param {object[]} parents - An array of the parent objects that have already been dereferenced
- * @param {object[]} processedObjects - An array of all the objects that have already been processed
- * @param {object} dereferencedCache - An map of all the dereferenced objects
+ * @param {Set<object>} parents - An array of the parent objects that have already been dereferenced
+ * @param {Set<object>} processedObjects - An array of all the objects that have already been processed
+ * @param {Map<string,object>} dereferencedCache - An map of all the dereferenced objects
  * @param {$Refs} $refs
  * @param {$RefParserOptions} options
  * @returns {{value: object, circular: boolean}}
@@ -41,18 +41,18 @@ function crawl (obj, path, pathFromRoot, parents, processedObjects, dereferenced
  circular: false
  };
 
- if (options.dereference.circular === "ignore" || processedObjects.indexOf(obj) === -1) {
+ if (options.dereference.circular === "ignore" || !processedObjects.has(obj)) {
  if (obj && typeof obj === "object" && !ArrayBuffer.isView(obj)) {
- parents.push(obj);
- processedObjects.push(obj);
+ parents.add(obj);
+ processedObjects.add(obj);
 
  if ($Ref.isAllowed$Ref(obj, options)) {
  dereferenced = dereference$Ref(obj, path, pathFromRoot, parents, processedObjects, dereferencedCache, $refs, options);
  result.circular = dereferenced.circular;
  result.value = dereferenced.value;
  }
  else {
- for (let key of Object.keys(obj)) {
+ for (const key of Object.keys(obj)) {
  let keyPath = Pointer.join(path, key);
  let keyPathFromRoot = Pointer.join(pathFromRoot, key);
  let value = obj[key];
@@ -67,7 +67,7 @@ function crawl (obj, path, pathFromRoot, parents, processedObjects, dereferenced
  }
  }
  else {
- if (parents.indexOf(value) === -1) {
+ if (!parents.has(value)) {
  dereferenced = crawl(value, keyPath, keyPathFromRoot, parents, processedObjects, dereferencedCache, $refs, options);
  circular = dereferenced.circular;
  // Avoid pointless mutations; breaks frozen objects to no profit
@@ -85,7 +85,7 @@ function crawl (obj, path, pathFromRoot, parents, processedObjects, dereferenced
  }
  }
 
- parents.pop();
+ parents.delete(obj);
  }
  }
 
@@ -98,9 +98,9 @@ function crawl (obj, path, pathFromRoot, parents, processedObjects, dereferenced
  * @param {{$ref: string}} $ref - The JSON Reference to resolve
  * @param {string} path - The full path of `$ref`, possibly with a JSON Pointer in the hash
  * @param {string} pathFromRoot - The path of `$ref` from the schema root
- * @param {object[]} parents - An array of the parent objects that have already been dereferenced
- * @param {object[]} processedObjects - An array of all the objects that have already been dereferenced
- * @param {object} dereferencedCache - An map of all the dereferenced objects
+ * @param {Set<object>} parents - An array of the parent objects that have already been dereferenced
+ * @param {Set<object>} processedObjects - An array of all the objects that have already been dereferenced
+ * @param {Map<string,object>} dereferencedCache - An map of all the dereferenced objects
  * @param {$Refs} $refs
  * @param {$RefParserOptions} options
  * @returns {{value: object, circular: boolean}}
@@ -110,9 +110,8 @@ function dereference$Ref ($ref, path, pathFromRoot, parents, processedObjects, d
 
  let $refPath = url.resolve(path, $ref.$ref);
 
- if (dereferencedCache[$refPath]) {
- const cache = dereferencedCache[$refPath];
-
+ const cache = dereferencedCache.get($refPath);
+ if (cache) {
  const refKeys = Object.keys($ref);
  if (refKeys.length > 1) {
  const extraKeys = {};
@@ -142,7 +141,7 @@ function dereference$Ref ($ref, path, pathFromRoot, parents, processedObjects, d
 
  // Check for circular references
  let directCircular = pointer.circular;
- let circular = directCircular || parents.indexOf(pointer.value) !== -1;
+ let circular = directCircular || parents.has(pointer.value);
  circular && foundCircularReference(path, $refs, options);
 
  // Dereference the JSON reference
@@ -175,7 +174,7 @@ function dereference$Ref ($ref, path, pathFromRoot, parents, processedObjects, d
 
  // only cache if no extra properties than $ref
  if (Object.keys($ref).length === 1) {
- dereferencedCache[$refPath] = dereferencedObject;
+ dereferencedCache.set($refPath, dereferencedObject);
  }
 
  return dereferencedObject;