Update Posts “using-js-sets-to-find-elements”

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