Added Simple Hash & Better Hash to Hash Table 🎨

Author: deadcoder0904

examples/datastructures/hash-table.js

@@ -0,0 +1,47 @@
+class HashTable {
+	constructor() {
+		this.table = new Array(137);
+	}
+
+	simpleHash(word) {
+		let total = 0;
+		for(let i = 0; i < word.length; i++)
+			total += word.charCodeAt(i);
+		return total % this.table.length;
+	}
+
+	betterHash(word) {
+		let total = 0;
+		for(let i = 0; i < word.length; i++)
+			total = 37 * total + word.charCodeAt(i);
+		return total % this.table.length;
+	}
+
+	put(value,whichHash) {
+		let pos;
+		if(whichHash == "simpleHash")
+			pos = this.simpleHash(value);
+		if(whichHash == "betterHash")
+			pos = this.betterHash(value);
+		this.table[pos] = value;
+	}
+
+	get(value,whichHash) {
+		let hash;
+		if(whichHash == "simpleHash")
+			hash = this.simpleHash(value);
+		if(whichHash == "betterHash")
+			hash = this.betterHash(value);
+		return this.table[hash];
+	}
+
+	showAll() {
+		let str = "";
+		for (let i = 0; i < this.table.length; i++)
+			if(this.table[i] !=undefined)
+				str += i + " : " + this.table[i] + "\n";
+		return str;
+	}
+}
+
+module.exports = HashTable;

test/datastructures/hash-table.test.js

@@ -0,0 +1,47 @@
+const expect = require('chai').expect;
+const HashTable = require('../../examples/datastructures/hash-table');
+
+describe('=> HASH TABLE', function() {
+	let names;
+	before(function () {
+		names = new HashTable();
+	});
+
+	it('should create an Empty Hash Table', function(done) {
+		expect(names.table).to.deep.equal([]);
+		done();
+	});
+
+	describe('=> simpleHash', function() {
+			before(function () {
+				names = new HashTable();
+			});
+
+		it('should put only 1 value of "Clayton" & "Raymond" in Hash Table bcz of Simple Hash', function(done) {
+			names.put("Clayton","simpleHash");
+			names.put("Raymond","simpleHash");
+			expect(names.showAll()).to.equal("45 : Raymond\n");
+			done();
+		});
+
+		after(function() {
+			names = new HashTable();
+		});
+	});
+
+	describe('=> betterHash', function() {
+		it('should put both values of "Clayton" & "Raymond" in Hash Table bcz of Simple Hash', function(done) {
+			names.put("Clayton","betterHash");
+			names.put("Raymond","betterHash");
+			expect(names.showAll()).to.equal("88 : Clayton\n92 : Raymond\n");
+			done();
+		});
+	});
+
+	it('should get value from Hash Table',function() {
+		names.put("New","betterHash");
+		expect(names.get("New","betterHash")).to.equal("New");
+		expect(names.get("xxx","betterHash")).to.equal(undefined);
+	});
+
+});