Merge pull request #56 from nuintun/patch-1

feat(hashmap): Better hash function using TextEncoder

Improves hash function using TextEncoder instead of codePointAt

Closes #55

src/data-structures/maps/hash-maps/hash-map.js

@@ -2,6 +2,9 @@
 const LinkedList = require('../../linked-lists/linked-list');
 const { nextPrime } = require('./primes');
 
+// Text encoding
+const encoding = new TextEncoder();
+
 /**
  * The map holds key-value pairs.
  * Any value (both objects and primitive values) may be used as either a key or a value.
@@ -50,12 +53,16 @@ class HashMap {
    * @return {integer} bucket index
    */
   hashFunction(key) {
-    const str = String(key);
+    const bytes = encoding.encode(key);
+    const { length } = bytes;
+
     let hash = 2166136261; // FNV_offset_basis (32 bit)
-    for (let i = 0; i < str.length; i += 1) {
-      hash ^= str.codePointAt(i); // XOR
+
+    for (let i = 0; i < length; ) {
+      hash ^= bytes[i++]; // XOR
       hash *= 16777619; // 32 bit FNV_prime
     }
+
     return (hash >>> 0) % this.buckets.length;
   }
   // end::hashFunction[]