From cad0e9e7f4cc5fd9f82cfd25223561d186804e22 Mon Sep 17 00:00:00 2001
From: Nikolay Kostyurin <JiLiZART@Gmail.com>
Date: Wed, 16 Dec 2020 23:55:17 +0200
Subject: [PATCH] perf(parser): cache nested tokens in Set to prevent
 deoptimization (#83)

---
 packages/bbob-parser/src/parse.js | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/packages/bbob-parser/src/parse.js b/packages/bbob-parser/src/parse.js
index 111f74c..545412c 100644
--- a/packages/bbob-parser/src/parse.js
+++ b/packages/bbob-parser/src/parse.js
@@ -49,23 +49,31 @@ const parse = (input, opts = {}) => {
 
   /**
    * Cache for nested tags checks
-   * @type {{}}
    */
-  const nestedTagsMap = {};
+  const nestedTagsMap = new Set();
 
+  /**
+   *
+   * @param token
+   * @returns {boolean}
+   */
   const isTokenNested = (token) => {
-    if (typeof nestedTagsMap[token.getValue()] === 'undefined') {
-      nestedTagsMap[token.getValue()] = tokenizer.isTokenNested(token);
+    const value = token.getValue();
+
+    if (!nestedTagsMap.has(value) && tokenizer.isTokenNested && tokenizer.isTokenNested(token)) {
+      nestedTagsMap.add(value);
+
+      return true;
     }
 
-    return nestedTagsMap[token.getValue()];
+    return nestedTagsMap.has(value);
   };
 
   /**
    * @param tagName
    * @returns {boolean}
    */
-  const isTagNested = (tagName) => !!nestedTagsMap[tagName];
+  const isTagNested = (tagName) => Boolean(nestedTagsMap.has(tagName));
 
   /**
    * @private