feat: implement hash table data structure class

Author: francislagares

src/hash-table/HashTable.ts

@@ -0,0 +1,49 @@
+export class HashTable {
+  protected size: number;
+  private data;
+
+  constructor(size: number) {
+    this.size = size;
+    this.data = new Array(size);
+  }
+
+  private hash(key: string) {
+    let hash = 0;
+    for (let i = 0; i < key.length; i++) {
+      hash = (hash + key.charCodeAt(i) * i) % this.data.length;
+    }
+    return hash;
+  }
+
+  public set(key: string, value: any) {
+    let address = this.hash(key);
+    if (!this.data[address]) {
+      this.data[address] = [];
+    }
+    this.data[address].push([key, value]);
+    return this.data;
+  }
+
+  public get(key: string) {
+    let address = this.hash(key);
+    const currentBucket = this.data[address];
+    if (currentBucket) {
+      for (let i = 0; i < currentBucket.length; i++) {
+        if (currentBucket[i][0] === key) {
+          return currentBucket[i][1];
+        }
+      }
+    }
+    return undefined;
+  }
+
+  public keys() {
+    const keysArray = [];
+    for (let i = 0; i < this.data.length; i++) {
+      if (this.data[i]) {
+        keysArray.push(this.data[i][0][0]);
+      }
+    }
+    return keysArray;
+  }
+}

src/index.ts

@@ -1,2 +1,3 @@
 console.log('Typescript Data Structures & Algorithms');
 import './arrays/arrayClass';
+import './hash-table/HashTable';