--update: added code for remove duplicates from string

Author: ashokdey

src/_Problems_/remove-duplicates/index.js

@@ -0,0 +1,25 @@
+function removeDuplicatesUsingHashTable(str) {
+  let result = '';
+  const charHash = {};
+
+  // eslint-disable-next-line no-restricted-syntax
+  for (const char of str) {
+    if (!charHash[char]) {
+      charHash[char] = char;
+    }
+  }
+
+  Object.keys(charHash).map((char) => {
+    result += char;
+  });
+  return result;
+}
+
+function removeDuplicatesUsingSet(str) {
+  return [...new Set(str)].join('');
+}
+
+module.exports = {
+  removeDuplicatesUsingHashTable,
+  removeDuplicatesUsingSet,
+};

src/_Problems_/remove-duplicates/remove-duplicates.test.js

@@ -0,0 +1,23 @@
+const { removeDuplicatesUsingHashTable, removeDuplicatesUsingSet } = require('.');
+
+describe('Remove Duplicates', () => {
+  describe('Using Hash Table', () => {
+    it('Should remove the duplicate chars from `apple`', () => {
+      expect(removeDuplicatesUsingHashTable('apple')).toEqual('aple');
+    });
+
+    it('Should return `bye` from `bye`', () => {
+      expect(removeDuplicatesUsingHashTable('bye')).toEqual('bye');
+    });
+  });
+
+  describe('Using ES6 Set', () => {
+    it('Should remove the duplicate chars from `apple`', () => {
+      expect(removeDuplicatesUsingSet('apple')).toEqual('aple');
+    });
+
+    it('Should return `bye` from `bye`', () => {
+      expect(removeDuplicatesUsingSet('bye')).toEqual('bye');
+    });
+  });
+});