From b19a1796ac49b4357d0b2332c829ea837dbbbea5 Mon Sep 17 00:00:00 2001
From: Tim van der Meij <timvandermeij@gmail.com>
Date: Sun, 12 Jul 2020 12:00:42 +0200
Subject: [PATCH] Convert `RefSetCache` to a proper class and to use a `Map`
 internally

Using a `Map` instead of an `Object` provides some advantages such as
cheaper ways to get the size of the cache, to find out if an entry is
contained in the cache and to iterate over the cache. Moreover, we can
clear and re-use the same `Map` object now instead of creating a new
one.
---
 src/core/primitives.js | 59 +++++++++++++++++++-----------------------
 1 file changed, 27 insertions(+), 32 deletions(-)

diff --git a/src/core/primitives.js b/src/core/primitives.js
index 9613e789e..f9c7ecbdb 100644
--- a/src/core/primitives.js
+++ b/src/core/primitives.js
@@ -239,46 +239,41 @@ class RefSet {
   }
 }
 
-var RefSetCache = (function RefSetCacheClosure() {
-  // eslint-disable-next-line no-shadow
-  function RefSetCache() {
-    this.dict = Object.create(null);
+class RefSetCache {
+  constructor() {
+    this._map = new Map();
   }
 
-  RefSetCache.prototype = {
-    get size() {
-      return Object.keys(this.dict).length;
-    },
+  get size() {
+    return this._map.size;
+  }
 
-    get: function RefSetCache_get(ref) {
-      return this.dict[ref.toString()];
-    },
+  get(ref) {
+    return this._map.get(ref.toString());
+  }
 
-    has: function RefSetCache_has(ref) {
-      return ref.toString() in this.dict;
-    },
+  has(ref) {
+    return this._map.has(ref.toString());
+  }
 
-    put: function RefSetCache_put(ref, obj) {
-      this.dict[ref.toString()] = obj;
-    },
+  put(ref, obj) {
+    this._map.set(ref.toString(), obj);
+  }
 
-    putAlias: function RefSetCache_putAlias(ref, aliasRef) {
-      this.dict[ref.toString()] = this.get(aliasRef);
-    },
+  putAlias(ref, aliasRef) {
+    this._map.set(ref.toString(), this.get(aliasRef));
+  }
 
-    forEach: function RefSetCache_forEach(callback) {
-      for (const i in this.dict) {
-        callback(this.dict[i]);
-      }
-    },
+  forEach(callback) {
+    for (const value of this._map.values()) {
+      callback(value);
+    }
+  }
 
-    clear: function RefSetCache_clear() {
-      this.dict = Object.create(null);
-    },
-  };
-
-  return RefSetCache;
-})();
+  clear() {
+    this._map.clear();
+  }
+}
 
 function isEOF(v) {
   return v === EOF;