From e40175d8d1ce04c33691137a4ee94af5353c7f60 Mon Sep 17 00:00:00 2001
From: Jo Wroten <jo@wroten.me>
Date: Tue, 9 Jul 2019 20:32:22 +0000
Subject: [PATCH] =?UTF-8?q?Update=20Posts=20=E2=80=9Cusing-js-sets-to-find?=
 =?UTF-8?q?-elements=E2=80=9D?=
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---
 .../posts/using-js-sets-to-find-elements.md   | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/content/posts/using-js-sets-to-find-elements.md b/content/posts/using-js-sets-to-find-elements.md
index 13fd937..51fabdf 100644
--- a/content/posts/using-js-sets-to-find-elements.md
+++ b/content/posts/using-js-sets-to-find-elements.md
@@ -8,7 +8,23 @@ description: >-
   loops.
 
 
-  https://gitlab.com/snippets/1873655
+  ```js
+
+  // Example Data
+
+  let hugeArray = [...Array(10000).keys()].map(id => { return {id}; }); // [{id:
+  0}, ..., {id: 9999}]
+
+  let needles = [1010, 2020, 3030, 4040, 5050, 6060, 7070, 8080, 9090];
+
+
+  // Finding matching elements
+
+  let needlesSet = new Set(needles);
+
+  let matches = hugeArray.filter(obj => needlesSet.has(obj.id));
+
+  ```
 ---
 Functionally for one check, this is identical to checking the `.indexOf()` or `.includes()` of an Array. However, in cases where you're filtering a large array down to match a list of ID's, for example, the nested looping can result in a performance hit. Traditionally hash tables were used for speeding up this search, but with ES2015 we can now leverage Sets which are easier to read and still result in a single loop that's equal to the length of the Array and no more. (Can be further optimized by ending when running out of needles)
 
@@ -21,3 +37,5 @@ let needles = [1010, 2020, 3030, 4040, 5050, 6060, 7070, 8080, 9090];
 let needlesSet = new Set(needles);
 let matches = hugeArray.filter(obj => needlesSet.has(obj.id));
 ```
+
+https://gitlab.com/snippets/1873655