remove_duplicates javascript

Author: williscool

javascript/interview_questions/remove_duplicates.js

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+/* 
+  remove duplicates from an array
+  
+  could have 0 elements
+  
+  could be any type of value
+
+*/
+
+function removeDuplicates(arr){
+
+    if(arr.length <= 1) return arr;
+    
+    var table = {};
+    var output = [];
+    var hash_key;
+    
+    for(var i = 0; i < arr.length; i++){
+        hash_key = JSON.stringify(arr[i]);
+        
+        if(!table[hash_key]){
+            output.push(arr[i]);
+        }
+        
+        table[hash_key] = true;
+    }
+    
+    return output;
+}
+
+module.exports = removeDuplicates;

javascript/test/interview_questions/remove_duplicates_test.js

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+var assert = require('assert');
+var removeDuplicates = require('../../interview_questions/remove_duplicates.js');
+
+describe('Remove Duplicates', function() {
+
+  describe('should work with arrays', function() {
+
+    it('that are empty', function() {
+      assert.deepEqual(removeDuplicates([]), []);
+    });
+
+    it('with no duplicates', function() {
+      assert.deepEqual(removeDuplicates([1,2]), [1,2]);
+    });
+
+    it('that have duplicates', function() {
+      assert.deepEqual(removeDuplicates([3,3,3]), [3]);
+    });
+
+    it('that contain objects', function() {
+
+      var Person = function(name) {
+          this.name = name;
+      };
+
+      Person.prototype = {
+          name: null
+      };
+
+      var albert = new Person('Albert');
+      var bob = new Person('Bob');
+      var bobAgain = new Person('Bob');
+
+      var input = [albert,bob, bobAgain];
+      
+      assert.deepEqual(removeDuplicates(input), [albert,bob]);
+    });
+
+  });
+
+});