From 61636fcf54587c5ee9cf8a8488aecf7614a3360a Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Mon, 24 Apr 2017 13:41:04 -0700
Subject: [PATCH 01/20] Update README and add CONTRACT file

---
 CONTRACT.md | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 README.md   |  5 ++++
 2 files changed, 74 insertions(+)
 create mode 100644 CONTRACT.md

diff --git a/CONTRACT.md b/CONTRACT.md
new file mode 100644
index 0000000..3d3b54d
--- /dev/null
+++ b/CONTRACT.md
@@ -0,0 +1,69 @@
+#158 Core Algorithms [Classic, Numeric, and Set]
+#filthy-gerbil
+Somaya Bounouar
+http://jsdev.learnersguild.org/goals/158-Core_Algorithms-Classic_Numeric_and_Set.html
+
+
+# Core Algorithms [Classic, Numeric, and Set]
+
+## Challenge Rating
+
+This goal will likely be within your ZPD if you...
+
+- Can write programs and tests using Node.js and npm
+- Can use problem decomposition to split difficult problems into smaller parts
+- Have used pseudocode as an intermediary step in writing a program
+- Are interested in common computer science algorithms
+- Are interested in critical thinking and problem solving
+
+## Description
+
+This is a sub-goal of [Core Algorithms][core-algos]. Reference that goal for more description, context, and resources.
+
+Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/blob/master/algorithms.md#classic), [Numeric](https://github.com/GuildCrafts/core-algorithms/blob/master/algorithms.md#numeric), and [Set Operations](https://github.com/GuildCrafts/core-algorithms/blob/master/algorithms.md#set-operations) algorithms, not the Sorting/Searching or Graphing/Geometry. That's a [separate goal][core-algos-adv]. :)
+
+## Specifications
+
+- [ ] Artifact produced is a fork of the [core-algorithms][core-algorithms] repo.
+- [ ] Can run all tests with `npm test`.
+- [ ] `makeChange()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `makeChange()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] `fizzBuzz()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `fizzBuzz()` exist.
+- [ ] `isPalindrome()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `isPalindrome()` exist with at least 2 unit tests using valid inputs.
+- [ ] `factorial()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `factorial()` exist with at least 2 unit tests using valid inputs.
+- [ ] `fibonacci()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `fibonacci()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] `collatzConjecture()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `collatzConjecture()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] `setUnion()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `setUnion()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] `setIntersection()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `setIntersection()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] `setComplement()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `setComplement()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] `setSymmetricDifference()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [ ] Tests for `setSymmetricDifference()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [ ] Repository includes a README file with basic installation and setup instructions.
+- [ ] All dependencies are properly declared in `package.json`.
+- [ ] All major features are added via pull requests with a clear description and concise commit messages.
+- [ ] Code uses a linter and there are no linting errors.
+- [ ] Variables, functions, files, etc. have appropriate and meaningful names.
+- [ ] Functions are small and serve a single purpose.
+- [ ] The artifact produced is properly licensed, preferably with the [MIT license][mit-license].
+
+### Stretch
+
+Pick a _different_ programming language from JavaScript (e.g. Ruby, Swift, Python, C, Java...) and write tests & implementations for each.
+
+- [ ] Can run all non-JavaScript tests with a single command.
+- [ ] For each algorithm identified above, there exists:
+  - [ ] a test file with multiple unit tests for each algorithm  _in a language other than JavaScript_.
+  - [ ] an implementation file with a correct implementation of the algorithm _in a language other than JavaScript_.
+
+
+[core-algos]: {{ site.url }}{% link _goals/123-Core_Algorithms.md %}
+[core-algos-adv]: {{ site.url }}{% link _goals/159-Core_Algorithms-Sorting_Searching_Graphing_and_Geometry.md %}
+[algorithms-list]: https://github.com/GuildCrafts/core-algorithms/blob/master/algorithms.md
diff --git a/README.md b/README.md
index 783e9c5..fa50efb 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,9 @@
 # Core Algorithms
+#158 Core Algorithms [Classic, Numeric, and Set]
+#filthy-gerbil
+Somaya Bounouar
+http://jsdev.learnersguild.org/goals/158-Core_Algorithms-Classic_Numeric_and_Set.html
+
 
 Tests and implementations for algorithms commonly used in job interviews. See the full list in the [algorithms.md](algorithms.md) file.
 

From 7f2ed9ba9e698f93ecf4fd16af42df0a4bf87019 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Mon, 24 Apr 2017 15:35:55 -0700
Subject: [PATCH 02/20] Complete makeChange algorithm w tests

---
 CONTRACT.md       |  4 ++--
 src/makeChange.js | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/CONTRACT.md b/CONTRACT.md
index 3d3b54d..b9b1429 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -24,9 +24,9 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 
 ## Specifications
 
-- [ ] Artifact produced is a fork of the [core-algorithms][core-algorithms] repo.
+- [x] Artifact produced is a fork of the [core-algorithms][core-algorithms] repo.
 - [ ] Can run all tests with `npm test`.
-- [ ] `makeChange()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] `makeChange()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `makeChange()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `fizzBuzz()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `fizzBuzz()` exist.
diff --git a/src/makeChange.js b/src/makeChange.js
index 59d89b1..ef234a6 100644
--- a/src/makeChange.js
+++ b/src/makeChange.js
@@ -1,3 +1,46 @@
+// makeChange:
+//
+// Given a price and an amount paid, return the number of coins in each denomination that should be given as change.
+//
+// Note: because JavaScript is bad at decimal math, the inputs are given as integers that represent dollar + cent amounts, so 139 = $1.39.
+//
+// makeChange({ price: 100, amountGiven: 100 })
+// // => { quarters: 0, dimes: 0, nickels: 0, pennies: 0 }
+//
+// makeChange({ price: 159, amountGiven: 200 })
+// // => { quarters: 1, dimes: 1, nickels: 1, pennies: 1 }
+//
+// makeChange({ price: 432, amountGiven: 500 })
+// // => { quarters: 2, dimes: 1, nickels: 1, pennies: 3 }
+
+
 export default function makeChange({price, amountGiven}) {
-  // your code here
+  var change = {
+    quarters: 0,
+    dimes: 0,
+    nickels: 0,
+    pennies: 0,
+  }
+  var result = amountGiven - price
+
+  if (result === 0) {
+    return change
+  }
+  while (result >= 25) {
+    result = result - 25
+    change.quarters += 1
+  }
+  while (result >= 10) {
+    result = result - 10
+    change.dimes += 1
+  }
+  while (result >= 5) {
+    result = result - 5
+    change.nickels += 1
+  }
+  while (result >= 1) {
+    result = result - 1
+    change.pennies += 1
+  }
+    return change
 }

From 6f4b5d89f416c5d3cf98ba6a5a0cfa0779d1aa53 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Mon, 24 Apr 2017 18:28:07 -0700
Subject: [PATCH 03/20] Add makeChange test for invalid inputs

---
 CONTRACT.md             |  8 ++++----
 src/makeChange.js       | 12 ++++++++----
 test/makeChange_test.js | 12 ++++++++++++
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/CONTRACT.md b/CONTRACT.md
index b9b1429..1377525 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -25,11 +25,11 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 ## Specifications
 
 - [x] Artifact produced is a fork of the [core-algorithms][core-algorithms] repo.
-- [ ] Can run all tests with `npm test`.
+- [x] Can run all tests with `npm test`.
 - [x] `makeChange()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `makeChange()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] `fizzBuzz()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `fizzBuzz()` exist.
+- [x] Tests for `makeChange()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `fizzBuzz()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `fizzBuzz()` exist.
 - [ ] `isPalindrome()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `isPalindrome()` exist with at least 2 unit tests using valid inputs.
 - [ ] `factorial()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
diff --git a/src/makeChange.js b/src/makeChange.js
index ef234a6..28834c8 100644
--- a/src/makeChange.js
+++ b/src/makeChange.js
@@ -14,14 +14,18 @@
 // // => { quarters: 2, dimes: 1, nickels: 1, pennies: 3 }
 
 
-export default function makeChange({price, amountGiven}) {
-  var change = {
+export default function makeChange(options) {
+  if (typeof options !== 'object') {
+    throw new Error('Invalid input format. Expected an object literal')
+  }
+  const {price, amountGiven} = options
+  let change = {
     quarters: 0,
     dimes: 0,
     nickels: 0,
     pennies: 0,
   }
-  var result = amountGiven - price
+  let result = amountGiven - price
 
   if (result === 0) {
     return change
@@ -42,5 +46,5 @@ export default function makeChange({price, amountGiven}) {
     result = result - 1
     change.pennies += 1
   }
-    return change
+  return change
 }
diff --git a/test/makeChange_test.js b/test/makeChange_test.js
index d17098e..2ca1a8a 100644
--- a/test/makeChange_test.js
+++ b/test/makeChange_test.js
@@ -50,4 +50,16 @@ describe('makeChange()', function(){
       pennies: 0,
     })
   })
+
+  it('throws an error when given invalid inputs', function() {
+    expect(function(){ makeChange(100, 170) }).to.throw(
+      'Invalid input format. Expected an object literal'
+    )
+  })
+
+  it('throws an error when given no arguments', function() {
+    expect(function(){ makeChange() }).to.throw(
+      'Invalid input format. Expected an object literal'
+    )
+  })
 })

From 2306267376bbf323f1b3a6bbb9f3b640331b31e4 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Mon, 24 Apr 2017 18:29:35 -0700
Subject: [PATCH 04/20] Complete fizzBuzz algorithm w tests

---
 src/fizzBuzz.js       | 26 ++++++++++++++++++++++++++
 test/fizzBuzz_test.js | 22 ++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 src/fizzBuzz.js
 create mode 100644 test/fizzBuzz_test.js

diff --git a/src/fizzBuzz.js b/src/fizzBuzz.js
new file mode 100644
index 0000000..e32601a
--- /dev/null
+++ b/src/fizzBuzz.js
@@ -0,0 +1,26 @@
+// fizzBuzz
+//
+// Return an array of numbers from 1 to 100.
+//
+// For multiples of three, use the string Fizz instead of the number and for multiples of five replace with Buzz.
+//
+// For numbers which are multiples of both three and five replace with FizzBuzz.
+//
+// fizzBuzz()
+// // => [1, 2, 'Fizz', 4, 'Buzz', 'Fizz', 7, 8, 'Fizz', 'Buzz', 11, 'Fizz', 13, 14, 'FizzBuzz', ...]
+
+export default function fizzBuzz() {
+  let fizzBuzzArray = []
+  for (var i = 1; i <= 100; i++){
+    if (i % 3 == 0 && i % 5 == 0) {
+      fizzBuzzArray.push('FizzBuzz')
+    } else if (i % 3 == 0) {
+      fizzBuzzArray.push('Fizz')
+    } else if (i % 5 == 0) {
+      fizzBuzzArray.push('Buzz')
+    } else {
+      fizzBuzzArray.push(i)
+    }
+  }
+  return fizzBuzzArray
+}
diff --git a/test/fizzBuzz_test.js b/test/fizzBuzz_test.js
new file mode 100644
index 0000000..4fe4fe9
--- /dev/null
+++ b/test/fizzBuzz_test.js
@@ -0,0 +1,22 @@
+import { expect } from 'chai'
+import fizzBuzz from '../src/fizzBuzz'
+
+describe('fizzBuzz()', function(){
+
+  it('should be a function', function(){
+    expect(fizzBuzz).to.be.a('function')
+  })
+
+  it('returns an array of 100 values', function() {
+    var fizzBuzzArray = fizzBuzz(100)
+    expect(fizzBuzzArray.length).to.deep.equal(100)
+  })
+
+  it("replace multiples of 3 as 'Fizz', multiples of 5 as 'Buzz' and multiples of 3 and 5 as 'FizzBuzz' and return numbers that aren't multiples of 3 or 5 ", function(){
+    var fizzBuzzArray = fizzBuzz(100)
+      expect(fizzBuzzArray[2]).to.eql('Fizz')
+      expect(fizzBuzzArray[4]).to.eql('Buzz')
+      expect(fizzBuzzArray[14]).to.eql('FizzBuzz')
+      expect(fizzBuzzArray[1]).to.eql(2)
+    })
+  })

From c8fdd34e7f21dcd44bee2752427ffbf838578256 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Mon, 24 Apr 2017 18:29:56 -0700
Subject: [PATCH 05/20] WIP isPalindrome

---
 src/isPalindrome.js       | 40 +++++++++++++++++++++++++++++++++++++++
 test/isPalindrome_test.js |  2 ++
 2 files changed, 42 insertions(+)
 create mode 100644 src/isPalindrome.js
 create mode 100644 test/isPalindrome_test.js

diff --git a/src/isPalindrome.js b/src/isPalindrome.js
new file mode 100644
index 0000000..f499d03
--- /dev/null
+++ b/src/isPalindrome.js
@@ -0,0 +1,40 @@
+// isPalindrome
+//
+// Determine if a string is a palindrome. Return true or false.
+//
+// Ignore punctuation, spacing, and case sensitivity.
+//
+// isPalindrome('radar')
+// // => true
+//
+// isPalindrome('bananas')
+// // => false
+//
+// isPalindrome('A man, a plan, a canal: Panama')
+// // => true
+
+export default function isPalindrome(string) {
+  var strToLowerCase = string.toLowerCase()
+  var strWithoutSpecialCharAndSpaces = strToLowerCase.replace(/[^a-zA-Z]/g, "")
+  var isPalindromeArray = strWithoutSpecialCharAndSpaces.split('')
+
+  var shiftArray = []
+  var popArray = []
+
+  for (var i = 0; i < isPalindromeArray.length; i++) {
+    shiftArray.push(isPalindromeArray.shift([i]))
+    popArray.push(isPalindromeArray.pop([i]))
+  }
+  console.log('shift', shiftArray)
+  console.log('pop', popArray)
+  //check if both arrays match
+  //return boolean
+}
+
+
+//regex to remove special characters and spaces
+//2 empty arrays
+//split string at characters
+//shift from beginning of string into 1st array
+//pop from end of string into 2nd array
+//check if both arrays match
diff --git a/test/isPalindrome_test.js b/test/isPalindrome_test.js
new file mode 100644
index 0000000..285b803
--- /dev/null
+++ b/test/isPalindrome_test.js
@@ -0,0 +1,2 @@
+import { expect } from 'chai'
+import isPalindrome from '../src/isPalindrome'

From b445096764171c68fbc3ab934a7227ecf07892bc Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 09:53:02 -0700
Subject: [PATCH 06/20] Complete isPalindrome algorithm w tests

---
 CONTRACT.md               |  4 ++--
 src/isPalindrome.js       | 20 ++++++++------------
 test/isPalindrome_test.js | 16 ++++++++++++++++
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/CONTRACT.md b/CONTRACT.md
index 1377525..831bfbc 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -30,8 +30,8 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `makeChange()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [x] `fizzBuzz()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `fizzBuzz()` exist.
-- [ ] `isPalindrome()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `isPalindrome()` exist with at least 2 unit tests using valid inputs.
+- [x] `isPalindrome()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `isPalindrome()` exist with at least 2 unit tests using valid inputs.
 - [ ] `factorial()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `factorial()` exist with at least 2 unit tests using valid inputs.
 - [ ] `fibonacci()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
diff --git a/src/isPalindrome.js b/src/isPalindrome.js
index f499d03..0a73cfa 100644
--- a/src/isPalindrome.js
+++ b/src/isPalindrome.js
@@ -25,16 +25,12 @@ export default function isPalindrome(string) {
     shiftArray.push(isPalindromeArray.shift([i]))
     popArray.push(isPalindromeArray.pop([i]))
   }
-  console.log('shift', shiftArray)
-  console.log('pop', popArray)
-  //check if both arrays match
-  //return boolean
-}
-
+  var shiftString = shiftArray.join('')
+  var popString = popArray.join('')
 
-//regex to remove special characters and spaces
-//2 empty arrays
-//split string at characters
-//shift from beginning of string into 1st array
-//pop from end of string into 2nd array
-//check if both arrays match
+  if (shiftString == popString) {
+    return true
+  } else {
+    return false
+  }
+}
diff --git a/test/isPalindrome_test.js b/test/isPalindrome_test.js
index 285b803..53a013b 100644
--- a/test/isPalindrome_test.js
+++ b/test/isPalindrome_test.js
@@ -1,2 +1,18 @@
 import { expect } from 'chai'
 import isPalindrome from '../src/isPalindrome'
+
+describe('isPalindrome', function() {
+
+  it('should be a function', function(){
+    expect(isPalindrome).to.be.a('function')
+  })
+
+  it('returns true if it is a palindrome', function() {
+    expect(isPalindrome('A man, a plan, a canal: Panama')).to.eql(true)
+  })
+
+  it('returns false if it is not a palindrome', function() {
+    expect(isPalindrome('bananas')).to.eql(false)
+  })
+
+})

From 3a8074a067d3d92d060d470973d29748528d4e93 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 10:45:35 -0700
Subject: [PATCH 07/20] Clean up code

---
 src/isPalindrome.js       | 4 ++--
 src/makeChange.js         | 2 +-
 test/isPalindrome_test.js | 1 -
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/isPalindrome.js b/src/isPalindrome.js
index 0a73cfa..8867c43 100644
--- a/src/isPalindrome.js
+++ b/src/isPalindrome.js
@@ -15,8 +15,8 @@
 
 export default function isPalindrome(string) {
   var strToLowerCase = string.toLowerCase()
-  var strWithoutSpecialCharAndSpaces = strToLowerCase.replace(/[^a-zA-Z]/g, "")
-  var isPalindromeArray = strWithoutSpecialCharAndSpaces.split('')
+  var cleanStr = strToLowerCase.replace(/[^a-zA-Z]/g, "")
+  var isPalindromeArray = cleanStr.split('')
 
   var shiftArray = []
   var popArray = []
diff --git a/src/makeChange.js b/src/makeChange.js
index 28834c8..6269a1b 100644
--- a/src/makeChange.js
+++ b/src/makeChange.js
@@ -16,7 +16,7 @@
 
 export default function makeChange(options) {
   if (typeof options !== 'object') {
-    throw new Error('Invalid input format. Expected an object literal')
+    throw new Error('Invalid input format. Expected an object')
   }
   const {price, amountGiven} = options
   let change = {
diff --git a/test/isPalindrome_test.js b/test/isPalindrome_test.js
index 53a013b..0b224f7 100644
--- a/test/isPalindrome_test.js
+++ b/test/isPalindrome_test.js
@@ -14,5 +14,4 @@ describe('isPalindrome', function() {
   it('returns false if it is not a palindrome', function() {
     expect(isPalindrome('bananas')).to.eql(false)
   })
-
 })

From 82dc880b0b8d8d779b1654dcafd25f590814dded Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 11:00:58 -0700
Subject: [PATCH 08/20] Complete factorial algorithm w tests

---
 CONTRACT.md             |  4 ++--
 src/factorial.js        | 17 +++++++++++++++++
 test/factorial_test.js  | 14 ++++++++++++++
 test/makeChange_test.js |  4 ++--
 4 files changed, 35 insertions(+), 4 deletions(-)
 create mode 100644 src/factorial.js
 create mode 100644 test/factorial_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index 831bfbc..31fbf2d 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -32,8 +32,8 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `fizzBuzz()` exist.
 - [x] `isPalindrome()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `isPalindrome()` exist with at least 2 unit tests using valid inputs.
-- [ ] `factorial()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `factorial()` exist with at least 2 unit tests using valid inputs.
+- [x] `factorial()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `factorial()` exist with at least 2 unit tests using valid inputs.
 - [ ] `fibonacci()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `fibonacci()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `collatzConjecture()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
diff --git a/src/factorial.js b/src/factorial.js
new file mode 100644
index 0000000..c15d20a
--- /dev/null
+++ b/src/factorial.js
@@ -0,0 +1,17 @@
+// factorial
+//
+// Return the factorial of a number.
+//
+// factorial(5)
+// // => 120
+
+export default function factorial(num) {
+var factorialElements = [num]
+for (var i = num; i > 1; i--) {
+factorialElements.push(i - 1)
+}
+console.log('array', factorialElements)
+return factorialElements.reduce(function(a,b){
+return a*b
+}, 1)
+}
diff --git a/test/factorial_test.js b/test/factorial_test.js
new file mode 100644
index 0000000..12daa9e
--- /dev/null
+++ b/test/factorial_test.js
@@ -0,0 +1,14 @@
+import { expect } from 'chai'
+import factorial from '../src/factorial'
+
+describe('factorial()', function(){
+
+  it('should be a function', function(){
+    expect(factorial).to.be.a('function')
+  })
+
+  it('returns the factorial of any fiven number', function() {
+    expect(factorial(5)).to.eql(120)
+    expect(factorial(4)).to.eql(24)
+  })
+})
diff --git a/test/makeChange_test.js b/test/makeChange_test.js
index 2ca1a8a..9956816 100644
--- a/test/makeChange_test.js
+++ b/test/makeChange_test.js
@@ -53,13 +53,13 @@ describe('makeChange()', function(){
 
   it('throws an error when given invalid inputs', function() {
     expect(function(){ makeChange(100, 170) }).to.throw(
-      'Invalid input format. Expected an object literal'
+      'Invalid input format. Expected an object'
     )
   })
 
   it('throws an error when given no arguments', function() {
     expect(function(){ makeChange() }).to.throw(
-      'Invalid input format. Expected an object literal'
+      'Invalid input format. Expected an object'
     )
   })
 })

From 25d0906f8bdf35630aaad47268f19397eae806e6 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 12:55:30 -0700
Subject: [PATCH 09/20] Complete fibonacci algorithm w tests

---
 CONTRACT.md            |  4 ++--
 src/fibonacci.js       | 24 ++++++++++++++++++++++++
 test/fibonacci_test.js | 18 ++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 src/fibonacci.js
 create mode 100644 test/fibonacci_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index 31fbf2d..c70420a 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -34,8 +34,8 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `isPalindrome()` exist with at least 2 unit tests using valid inputs.
 - [x] `factorial()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `factorial()` exist with at least 2 unit tests using valid inputs.
-- [ ] `fibonacci()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `fibonacci()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `fibonacci()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `fibonacci()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `collatzConjecture()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `collatzConjecture()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setUnion()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
diff --git a/src/fibonacci.js b/src/fibonacci.js
new file mode 100644
index 0000000..88a9a4a
--- /dev/null
+++ b/src/fibonacci.js
@@ -0,0 +1,24 @@
+// fibonacci
+//
+// Return an array of Fibonacci numbers to the nth position.
+//
+// fibonacci(10)
+// // => [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
+
+export default function fibonacci(num) {
+  if (typeof num !== 'number') {
+    throw new Error('Invalid input format. Expected a number')
+  }
+  var first = 0
+  var second = 1
+  var result
+  var fibonacciArr = [0]
+
+  for (var i = 1; i < num; i++) {
+    result = first + second
+    first = second
+    second = result
+    fibonacciArr.push(first)
+  }
+  return fibonacciArr
+}
diff --git a/test/fibonacci_test.js b/test/fibonacci_test.js
new file mode 100644
index 0000000..06154f6
--- /dev/null
+++ b/test/fibonacci_test.js
@@ -0,0 +1,18 @@
+import { expect } from 'chai'
+import fibonacci from '../src/fibonacci'
+
+describe ('fibonacci', function(){
+
+  it('should be a function', function() {
+    expect(fibonacci).to.be.a('function')
+  })
+
+  it('returns an array of Fibonacci numbers to the nth position.', function() {
+    expect(fibonacci(10)).to.eql([0, 1, 1, 2, 3, 5, 8, 13, 21, 34])
+    expect(fibonacci(5)).to.eql([0, 1, 1, 2, 3])
+  })
+
+  it('throws an error when given invalid inputs', function() {
+    expect(function() {fibonacci('five') }).to.throw('Invalid input format. Expected a number')
+  })
+})

From 2e657470900797801077b5094f85db7bc56b54bf Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 14:12:18 -0700
Subject: [PATCH 10/20] Complete collatzConjecture algorithm w tests

---
 CONTRACT.md                    |  4 ++--
 src/collatzConjecture.js       | 32 ++++++++++++++++++++++++++++++++
 test/collatzConjecture_test.js | 18 ++++++++++++++++++
 3 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 src/collatzConjecture.js
 create mode 100644 test/collatzConjecture_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index c70420a..5b01d97 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -36,8 +36,8 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `factorial()` exist with at least 2 unit tests using valid inputs.
 - [x] `fibonacci()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `fibonacci()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] `collatzConjecture()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `collatzConjecture()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `collatzConjecture()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `collatzConjecture()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setUnion()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `setUnion()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setIntersection()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
diff --git a/src/collatzConjecture.js b/src/collatzConjecture.js
new file mode 100644
index 0000000..3f5a5e1
--- /dev/null
+++ b/src/collatzConjecture.js
@@ -0,0 +1,32 @@
+// collatzConjecture
+//
+// Return the Collatz sequence for a given number.
+//
+// The Collatz sequence for any positive integer n is defined as follows:
+//
+// If n is even, divide it by 2 to get n / 2. If n is odd, multiply it by 3 and add 1 to obtain 3n + 1. Repeat the process until you reach 1.
+// collatzConjecture(1)
+// // => [1]
+//
+// collatzConjecture(7)
+// // => [7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1]
+
+
+export default function collatzConjecture(num) {
+  if (!Number.isInteger(num) || num < 0) {
+    throw new Error('Invalid input format. Expected a positive integer')
+  }
+  let collatzArr = [num]
+  let result = num
+
+  while (result > 1) {
+    if (result % 2 === 0) {
+      result = result / 2
+      collatzArr.push(result)
+    } else {
+      result = (result * 3) + 1
+      collatzArr.push(result)
+    }
+  }
+  return collatzArr
+}
diff --git a/test/collatzConjecture_test.js b/test/collatzConjecture_test.js
new file mode 100644
index 0000000..c895ca0
--- /dev/null
+++ b/test/collatzConjecture_test.js
@@ -0,0 +1,18 @@
+import { expect } from 'chai'
+import collatzConjecture from '../src/collatzConjecture'
+
+describe('collatzConjecture()', function(){
+
+  it('should be a function', function(){
+    expect(collatzConjecture).to.be.a('function')
+  })
+  it('returns a Collatz sequence for any positive integer', function(){
+    expect(collatzConjecture(7)).to.eql([7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1])
+    expect(collatzConjecture(3)).to.eql([3, 10, 5, 16, 8, 4, 2, 1])
+  })
+
+  it('throws an error for any invalid inputs', function() {
+    expect(function() {collatzConjecture(-1)}).to.throw('Invalid input format. Expected a positive integer')
+    expect(function() {collatzConjecture('seven')}).to.throw('Invalid input format. Expected a positive integer')
+  })
+})

From e07820ee2d2f791f918546138f17d07ce5692820 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 14:14:17 -0700
Subject: [PATCH 11/20] Clean code

---
 src/factorial.js | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/factorial.js b/src/factorial.js
index c15d20a..cb8372f 100644
--- a/src/factorial.js
+++ b/src/factorial.js
@@ -6,12 +6,11 @@
 // // => 120
 
 export default function factorial(num) {
-var factorialElements = [num]
-for (var i = num; i > 1; i--) {
-factorialElements.push(i - 1)
-}
-console.log('array', factorialElements)
-return factorialElements.reduce(function(a,b){
-return a*b
-}, 1)
+  var factorialElements = [num]
+  for (var i = num; i > 1; i--) {
+  factorialElements.push(i - 1)
+  }
+  return factorialElements.reduce(function(a,b){
+  return a*b
+  }, 1)
 }

From cecde9c8b3cb5a8f5bb94539efda2f737b23ed72 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 15:45:44 -0700
Subject: [PATCH 12/20] Complete setUnion algorithm w tests

---
 CONTRACT.md           |  4 ++--
 src/setUnion.js       | 22 ++++++++++++++++++++++
 test/setUnion_test.js | 20 ++++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 src/setUnion.js
 create mode 100644 test/setUnion_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index 5b01d97..1eb880f 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -38,8 +38,8 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `fibonacci()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [x] `collatzConjecture()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `collatzConjecture()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] `setUnion()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `setUnion()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `setUnion()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `setUnion()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setIntersection()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `setIntersection()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setComplement()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
diff --git a/src/setUnion.js b/src/setUnion.js
new file mode 100644
index 0000000..79f5b94
--- /dev/null
+++ b/src/setUnion.js
@@ -0,0 +1,22 @@
+// setUnion
+//
+// Return the union of two sets.
+//
+// const a = [1, 2, 3, 4]
+// const b = [2, 4, 6, 8]
+// setUnion(a, b)
+// // => [1, 2, 3, 4, 6, 8]
+
+export default function setUnion(a, b){
+  if (!Array.isArray(a) || !Array.isArray(b)){
+    throw new Error('Invalid input format. Expected two arrays')
+  }
+  let concatArr = a.concat(b)
+  let sortedArr = concatArr.sort()
+
+  function isUnique(value, index, array){
+    return array.indexOf(value) === index
+  }
+  let filteredArr = sortedArr.filter(isUnique)
+  return filteredArr
+}
diff --git a/test/setUnion_test.js b/test/setUnion_test.js
new file mode 100644
index 0000000..6813273
--- /dev/null
+++ b/test/setUnion_test.js
@@ -0,0 +1,20 @@
+import { expect } from 'chai'
+import setUnion from '../src/setUnion'
+
+describe('setUnion', function(){
+
+  it('should be a function', function() {
+    expect(setUnion).to.be.a('function')
+  })
+
+  it('returns the union of two sets', function() {
+    expect(setUnion([1,2,3,4],[2,4,6,8])).to.eql([1, 2, 3, 4, 6, 8])
+    expect(setUnion([2,3,4,4], [1,2,3,4]).to.eqal([1,2,3,4])
+  })
+
+  it('throws an error when given invalid inputs', function() {
+    expect(function() {setUnion('string')}).to.throw(
+      'Invalid input format. Expected two arrays'
+    )
+  })
+})

From 80095c9daaccf2c8d0c378436246b7d8d4dbcefa Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 16:10:59 -0700
Subject: [PATCH 13/20] Complete setIntersection w tests

---
 CONTRACT.md                  | 10 +++++-----
 src/setIntersection.js       | 23 +++++++++++++++++++++++
 test/setIntersection_test.js | 20 ++++++++++++++++++++
 test/setUnion_test.js        |  2 +-
 4 files changed, 49 insertions(+), 6 deletions(-)
 create mode 100644 src/setIntersection.js
 create mode 100644 test/setIntersection_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index 1eb880f..28e9da0 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -40,19 +40,19 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `collatzConjecture()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [x] `setUnion()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `setUnion()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] `setIntersection()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `setIntersection()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `setIntersection()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `setIntersection()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setComplement()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `setComplement()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setSymmetricDifference()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `setSymmetricDifference()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] Repository includes a README file with basic installation and setup instructions.
-- [ ] All dependencies are properly declared in `package.json`.
+- [x] All dependencies are properly declared in `package.json`.
 - [ ] All major features are added via pull requests with a clear description and concise commit messages.
 - [ ] Code uses a linter and there are no linting errors.
 - [ ] Variables, functions, files, etc. have appropriate and meaningful names.
-- [ ] Functions are small and serve a single purpose.
-- [ ] The artifact produced is properly licensed, preferably with the [MIT license][mit-license].
+- [] Functions are small and serve a single purpose.
+- [x] The artifact produced is properly licensed, preferably with the [MIT license][mit-license].
 
 ### Stretch
 
diff --git a/src/setIntersection.js b/src/setIntersection.js
new file mode 100644
index 0000000..a5a1118
--- /dev/null
+++ b/src/setIntersection.js
@@ -0,0 +1,23 @@
+// setIntersection
+//
+// Return the intersection of two sets.
+//
+// const a = [1, 2, 3, 4]
+// const b = [2, 4, 6, 8]
+// setIntersection(a, b)
+// // => [2, 4]
+
+
+export default function setIntersection(a, b){
+  if ( !Array.isArray(a) || !Array.isArray(b) ) {
+    throw new Error('Invalid input format. Expected two arrays')
+  }
+  let concatArr = a.concat(b)
+  let sortedArr = concatArr.sort()
+
+  function isDuplicate(value, index, array){
+    return array.indexOf(value) !== index
+  }
+  let filteredArr = sortedArr.filter(isDuplicate)
+  return filteredArr
+}
diff --git a/test/setIntersection_test.js b/test/setIntersection_test.js
new file mode 100644
index 0000000..871a6a0
--- /dev/null
+++ b/test/setIntersection_test.js
@@ -0,0 +1,20 @@
+import { expect } from 'chai'
+import setIntersection from '../src/setIntersection'
+
+describe('setIntersection', function(){
+
+  it('should be a function', function() {
+    expect(setIntersection).to.be.a('function')
+  })
+
+  it('returns the intersection of two sets', function () {
+    expect(setIntersection([1, 2, 3, 4],[2, 4, 6, 8])).to.eql([2,4])
+    expect(setIntersection([82,90,1], [1, 2, 90])).to.eql([1,90])
+  })
+
+  it('throws an error when given invalid inputs', function() {
+    expect(function() {setIntersection('string')}).to.throw(
+      'Invalid input format. Expected two arrays'
+    )
+  })
+})
diff --git a/test/setUnion_test.js b/test/setUnion_test.js
index 6813273..154031e 100644
--- a/test/setUnion_test.js
+++ b/test/setUnion_test.js
@@ -9,7 +9,7 @@ describe('setUnion', function(){
 
   it('returns the union of two sets', function() {
     expect(setUnion([1,2,3,4],[2,4,6,8])).to.eql([1, 2, 3, 4, 6, 8])
-    expect(setUnion([2,3,4,4], [1,2,3,4]).to.eqal([1,2,3,4])
+    expect(setUnion([2,3,4,4],[1,2,3,4])).to.eql([1,2,3,4])
   })
 
   it('throws an error when given invalid inputs', function() {

From d9697a3d0065681bb38a91544651082b4242231b Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Tue, 25 Apr 2017 17:53:59 -0700
Subject: [PATCH 14/20] Complete setComplement algorithm w tests

---
 CONTRACT.md                |  4 ++--
 src/setComplement.js       | 22 ++++++++++++++++++++++
 test/setComplement_test.js | 27 +++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 src/setComplement.js
 create mode 100644 test/setComplement_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index 28e9da0..c91e6fb 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -42,8 +42,8 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `setUnion()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [x] `setIntersection()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `setIntersection()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] `setComplement()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `setComplement()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `setComplement()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `setComplement()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] `setSymmetricDifference()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [ ] Tests for `setSymmetricDifference()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] Repository includes a README file with basic installation and setup instructions.
diff --git a/src/setComplement.js b/src/setComplement.js
new file mode 100644
index 0000000..208675c
--- /dev/null
+++ b/src/setComplement.js
@@ -0,0 +1,22 @@
+// setComplement
+//
+// Return the complement of two sets.
+//
+// const a = [1, 2, 3, 4]
+// const b = [2, 4, 6, 8]
+// setComplement(a, b)
+// // => [6, 8]
+
+
+export default function setComplement(setA, setB) {
+  if ( !Array.isArray(setA) || !Array.isArray(setB) ) {
+    throw new Error('Invalid input format. Expected two arrays')
+  }
+  let complementArray = []
+  for(let element of setB) {
+    if(!setA.includes(element)) {
+      complementArray.push(element)
+    }
+  }
+  return complementArray
+ }
diff --git a/test/setComplement_test.js b/test/setComplement_test.js
new file mode 100644
index 0000000..a8159ec
--- /dev/null
+++ b/test/setComplement_test.js
@@ -0,0 +1,27 @@
+import { expect } from 'chai'
+import setComplement from '../src/setComplement'
+
+describe('setComplement', function(){
+
+  it('should be a function', function() {
+    expect(setComplement).to.be.a('function')
+  })
+
+  it('should show the items from set B that are not present in set A', function() {
+    const setA = ['fluffy', 'cat', 'scratchy']
+    const setB = ['scratchy', 'fluffy', 'dog']
+    expect(setComplement(setA, setB)).to.eql(['dog'])
+  })
+
+  it('should show empty set if no items in B are not in A', function() {
+    const setA = ['fluffy', 'cat', 'scratchy']
+    const setB = ['scratchy', 'fluffy']
+    expect(setComplement(setA, setB)).to.eql([])
+  })
+
+  it('throws an error when given invalid inputs', function() {
+    expect(function() {setComplement({}, false)}).to.throw(
+      'Invalid input format. Expected two arrays'
+    )
+  })
+})

From 41d8ce9c525ac0098d22f5cd7aa2a07e396ee464 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Wed, 26 Apr 2017 14:54:34 -0700
Subject: [PATCH 15/20] Complete setSymmetricDifference algorithm w tests

---
 CONTRACT.md                         | 10 +++++-----
 src/factorial.js                    | 22 ++++++++++++++-------
 src/setSymmetricDifference.js       | 30 +++++++++++++++++++++++++++++
 test/setSymmetricDifference_test.js | 20 +++++++++++++++++++
 4 files changed, 70 insertions(+), 12 deletions(-)
 create mode 100644 src/setSymmetricDifference.js
 create mode 100644 test/setSymmetricDifference_test.js

diff --git a/CONTRACT.md b/CONTRACT.md
index c91e6fb..7b1f973 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -44,14 +44,14 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `setIntersection()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [x] `setComplement()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `setComplement()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] `setSymmetricDifference()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
-- [ ] Tests for `setSymmetricDifference()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
+- [x] `setSymmetricDifference()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
+- [x] Tests for `setSymmetricDifference()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [ ] Repository includes a README file with basic installation and setup instructions.
 - [x] All dependencies are properly declared in `package.json`.
-- [ ] All major features are added via pull requests with a clear description and concise commit messages.
+- [x] All major features are added via pull requests with a clear description and concise commit messages.
 - [ ] Code uses a linter and there are no linting errors.
-- [ ] Variables, functions, files, etc. have appropriate and meaningful names.
-- [] Functions are small and serve a single purpose.
+- [x] Variables, functions, files, etc. have appropriate and meaningful names.
+- [ ] Functions are small and serve a single purpose.
 - [x] The artifact produced is properly licensed, preferably with the [MIT license][mit-license].
 
 ### Stretch
diff --git a/src/factorial.js b/src/factorial.js
index cb8372f..3b13a65 100644
--- a/src/factorial.js
+++ b/src/factorial.js
@@ -6,11 +6,19 @@
 // // => 120
 
 export default function factorial(num) {
-  var factorialElements = [num]
-  for (var i = num; i > 1; i--) {
-  factorialElements.push(i - 1)
+    var accumulator = num
+    for (var i = num; i > 1; i--) {
+    accumulator = accumulator * (i - 1)
+    }
+    return accumulator
   }
-  return factorialElements.reduce(function(a,b){
-  return a*b
-  }, 1)
-}
+
+//Other way:
+//   var factorialElements = [num]
+//   for (var i = num; i > 1; i--) {
+//   factorialElements.push(i - 1)
+//   }
+//   return factorialElements.reduce(function(a,b){
+//   return a*b
+//   }, 1)
+// }
diff --git a/src/setSymmetricDifference.js b/src/setSymmetricDifference.js
new file mode 100644
index 0000000..945cec0
--- /dev/null
+++ b/src/setSymmetricDifference.js
@@ -0,0 +1,30 @@
+// setSymmetricDifference
+//
+// Return the symmetric difference of two sets.
+//
+// const a = [1, 2, 3, 4]
+// const b = [2, 4, 6, 8]
+// setSymmetricDifference(a, b)
+// // => [1, 3, 6, 8]
+
+
+export default function setSymmetricDifference(setA, setB) {
+  if ( !Array.isArray(setA) || !Array.isArray(setB) ) {
+    throw new Error('Invalid input format. Expected two arrays')
+  }
+  let complementArray = []
+  
+  for(let element of setB) {
+    if(!setA.includes(element)) {
+      complementArray.push(element)
+    }
+  }
+  for(let element of setA){
+    if(!setB.includes(element)) {
+      complementArray.push(element)
+    }
+  }
+  return complementArray.sort()
+  }
+
+//
diff --git a/test/setSymmetricDifference_test.js b/test/setSymmetricDifference_test.js
new file mode 100644
index 0000000..11f9554
--- /dev/null
+++ b/test/setSymmetricDifference_test.js
@@ -0,0 +1,20 @@
+import { expect } from 'chai'
+import setSymmetricDifference from '../src/setSymmetricDifference'
+
+
+
+describe('setSymmetricDifference', function() {
+
+  it('should be a function', function() {
+    expect(setSymmetricDifference).to.be.a('function')
+  })
+
+  it('returns the symmetric difference of two sets', function() {
+    expect(setSymmetricDifference([1, 2, 3, 4], [2, 4, 6, 8])).to.eql([1, 3, 6, 8])
+  })
+  
+  it('throws an error when given invalid inputs', function() {
+    expect(function() {setSymmetricDifference('string', [1,2])}).
+    to.throw('Invalid input format. Expected two arrays')
+  })
+})

From 8c3b3523aa5b191f2669ebe1010bca82cf9799c3 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Wed, 26 Apr 2017 17:52:41 -0700
Subject: [PATCH 16/20] Add ESLint and clean code

---
 .eslintrc.json                | 28 ++++++++++++++++++++++++++++
 README.md                     |  9 ++++++++-
 package.json                  |  1 +
 src/factorial.js              |  8 ++++----
 src/isPalindrome.js           |  2 +-
 src/setComplement.js          |  2 +-
 src/setSymmetricDifference.js |  4 ++--
 test/fizzBuzz_test.js         | 10 +++++-----
 8 files changed, 50 insertions(+), 14 deletions(-)
 create mode 100644 .eslintrc.json

diff --git a/.eslintrc.json b/.eslintrc.json
new file mode 100644
index 0000000..0cf2f93
--- /dev/null
+++ b/.eslintrc.json
@@ -0,0 +1,28 @@
+{
+    "env": {
+        "es6": true,
+        "node": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "sourceType": "module"
+    },
+    "rules": {
+        "indent": [
+            "error",
+            2
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "single"
+        ],
+        "semi": [
+            "error",
+            "never"
+        ]
+    }
+}
diff --git a/README.md b/README.md
index fa50efb..f492cc5 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,14 @@ Base repository for the [Core Algorithms](http://jsdev.learnersguild.org/goals/1
 
 ## Installation and Setup
 
-_Fill this out_
+
+
+Use the "npm i" command to install your dependencies.
+
+Use the "npm run test" command to run your tests in the terminal.
+
+Use the "npm install --save-dev eslint" command to install the linter ESlint.
+Run the "eslint --init" command to configure ESlint.
 
 ## Usage and Examples
 
diff --git a/package.json b/package.json
index 71f93c5..809abf3 100644
--- a/package.json
+++ b/package.json
@@ -8,6 +8,7 @@
     "babel-preset-env": "^1.1.4",
     "babel-register": "^6.18.0",
     "chai": "~1.8.0",
+    "eslint": "^3.19.0",
     "mocha": "2.0.1"
   },
   "scripts": {
diff --git a/src/factorial.js b/src/factorial.js
index 3b13a65..20ff181 100644
--- a/src/factorial.js
+++ b/src/factorial.js
@@ -6,12 +6,12 @@
 // // => 120
 
 export default function factorial(num) {
-    var accumulator = num
-    for (var i = num; i > 1; i--) {
+  var accumulator = num
+  for (var i = num; i > 1; i--) {
     accumulator = accumulator * (i - 1)
-    }
-    return accumulator
   }
+  return accumulator
+}
 
 //Other way:
 //   var factorialElements = [num]
diff --git a/src/isPalindrome.js b/src/isPalindrome.js
index 8867c43..714cee7 100644
--- a/src/isPalindrome.js
+++ b/src/isPalindrome.js
@@ -15,7 +15,7 @@
 
 export default function isPalindrome(string) {
   var strToLowerCase = string.toLowerCase()
-  var cleanStr = strToLowerCase.replace(/[^a-zA-Z]/g, "")
+  var cleanStr = strToLowerCase.replace(/[^a-zA-Z]/g, '')
   var isPalindromeArray = cleanStr.split('')
 
   var shiftArray = []
diff --git a/src/setComplement.js b/src/setComplement.js
index 208675c..75210b3 100644
--- a/src/setComplement.js
+++ b/src/setComplement.js
@@ -19,4 +19,4 @@ export default function setComplement(setA, setB) {
     }
   }
   return complementArray
- }
+}
diff --git a/src/setSymmetricDifference.js b/src/setSymmetricDifference.js
index 945cec0..6db53a9 100644
--- a/src/setSymmetricDifference.js
+++ b/src/setSymmetricDifference.js
@@ -13,7 +13,7 @@ export default function setSymmetricDifference(setA, setB) {
     throw new Error('Invalid input format. Expected two arrays')
   }
   let complementArray = []
-  
+
   for(let element of setB) {
     if(!setA.includes(element)) {
       complementArray.push(element)
@@ -25,6 +25,6 @@ export default function setSymmetricDifference(setA, setB) {
     }
   }
   return complementArray.sort()
-  }
+}
 
 //
diff --git a/test/fizzBuzz_test.js b/test/fizzBuzz_test.js
index 4fe4fe9..7f6cb4c 100644
--- a/test/fizzBuzz_test.js
+++ b/test/fizzBuzz_test.js
@@ -14,9 +14,9 @@ describe('fizzBuzz()', function(){
 
   it("replace multiples of 3 as 'Fizz', multiples of 5 as 'Buzz' and multiples of 3 and 5 as 'FizzBuzz' and return numbers that aren't multiples of 3 or 5 ", function(){
     var fizzBuzzArray = fizzBuzz(100)
-      expect(fizzBuzzArray[2]).to.eql('Fizz')
-      expect(fizzBuzzArray[4]).to.eql('Buzz')
-      expect(fizzBuzzArray[14]).to.eql('FizzBuzz')
-      expect(fizzBuzzArray[1]).to.eql(2)
-    })
+    expect(fizzBuzzArray[2]).to.eql('Fizz')
+    expect(fizzBuzzArray[4]).to.eql('Buzz')
+    expect(fizzBuzzArray[14]).to.eql('FizzBuzz')
+    expect(fizzBuzzArray[1]).to.eql(2)
   })
+})

From 50024850250e88f46b17335d63295ac1b616105a Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Thu, 27 Apr 2017 12:38:48 -0700
Subject: [PATCH 17/20] Fix linting errors

---
 .eslintrc.json        | 3 ++-
 CONTRACT.md           | 4 ++--
 README.md             | 5 ++---
 test/fizzBuzz_test.js | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/.eslintrc.json b/.eslintrc.json
index 0cf2f93..8b2834c 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,7 +1,8 @@
 {
     "env": {
         "es6": true,
-        "node": true
+        "node": true,
+        "mocha": true
     },
     "extends": "eslint:recommended",
     "parserOptions": {
diff --git a/CONTRACT.md b/CONTRACT.md
index 7b1f973..84a88cf 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -49,9 +49,9 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [ ] Repository includes a README file with basic installation and setup instructions.
 - [x] All dependencies are properly declared in `package.json`.
 - [x] All major features are added via pull requests with a clear description and concise commit messages.
-- [ ] Code uses a linter and there are no linting errors.
+- [x] Code uses a linter and there are no linting errors.
 - [x] Variables, functions, files, etc. have appropriate and meaningful names.
-- [ ] Functions are small and serve a single purpose.
+- [x] Functions are small and serve a single purpose.
 - [x] The artifact produced is properly licensed, preferably with the [MIT license][mit-license].
 
 ### Stretch
diff --git a/README.md b/README.md
index f492cc5..9c13d91 100644
--- a/README.md
+++ b/README.md
@@ -11,14 +11,13 @@ Base repository for the [Core Algorithms](http://jsdev.learnersguild.org/goals/1
 
 ## Installation and Setup
 
-
-
 Use the "npm i" command to install your dependencies.
 
 Use the "npm run test" command to run your tests in the terminal.
 
 Use the "npm install --save-dev eslint" command to install the linter ESlint.
-Run the "eslint --init" command to configure ESlint.
+  Use the "eslint --init" command to configure ESlint.
+  Use the "eslint [filename or folder name]" command to lint through your files.  
 
 ## Usage and Examples
 
diff --git a/test/fizzBuzz_test.js b/test/fizzBuzz_test.js
index 7f6cb4c..befb983 100644
--- a/test/fizzBuzz_test.js
+++ b/test/fizzBuzz_test.js
@@ -12,7 +12,7 @@ describe('fizzBuzz()', function(){
     expect(fizzBuzzArray.length).to.deep.equal(100)
   })
 
-  it("replace multiples of 3 as 'Fizz', multiples of 5 as 'Buzz' and multiples of 3 and 5 as 'FizzBuzz' and return numbers that aren't multiples of 3 or 5 ", function(){
+  it('replace multiples of 3 as \'Fizz\', multiples of 5 as \'Buzz\' and multiples of 3 and 5 as \'FizzBuzz\' and return numbers that aren\'t multiples of 3 or 5 ', function(){
     var fizzBuzzArray = fizzBuzz(100)
     expect(fizzBuzzArray[2]).to.eql('Fizz')
     expect(fizzBuzzArray[4]).to.eql('Buzz')

From c8b7754bc31cebc920766c7d22b3da7d45cb1c5c Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Thu, 27 Apr 2017 15:13:56 -0700
Subject: [PATCH 18/20] Add setup instructions in README file

---
 CONTRACT.md |  2 +-
 README.md   | 10 +++-------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/CONTRACT.md b/CONTRACT.md
index 84a88cf..d228caf 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -46,7 +46,7 @@ Complete **ONLY** the [Classic](https://github.com/GuildCrafts/core-algorithms/b
 - [x] Tests for `setComplement()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
 - [x] `setSymmetricDifference()` algorithm is implemented according to the description in [algorithms.md][algorithms-list].
 - [x] Tests for `setSymmetricDifference()` exist with at least 2 unit tests using valid inputs, and at least 1 unit test using invalid inputs.
-- [ ] Repository includes a README file with basic installation and setup instructions.
+- [x] Repository includes a README file with basic installation and setup instructions.
 - [x] All dependencies are properly declared in `package.json`.
 - [x] All major features are added via pull requests with a clear description and concise commit messages.
 - [x] Code uses a linter and there are no linting errors.
diff --git a/README.md b/README.md
index 9c13d91..18769e8 100644
--- a/README.md
+++ b/README.md
@@ -11,14 +11,10 @@ Base repository for the [Core Algorithms](http://jsdev.learnersguild.org/goals/1
 
 ## Installation and Setup
 
-Use the "npm i" command to install your dependencies.
+Use the "npm i" command to install the dependencies.
 
-Use the "npm run test" command to run your tests in the terminal.
+Use the "npm run test" command to run the tests in the terminal.
 
-Use the "npm install --save-dev eslint" command to install the linter ESlint.
+Use the "npm install --save-dev eslint" command to install the linter ESlint in the JSON file.
   Use the "eslint --init" command to configure ESlint.
   Use the "eslint [filename or folder name]" command to lint through your files.  
-
-## Usage and Examples
-
-_...and this_

From 6267dad1a0b68620e59053ac6f3996ebab0f9669 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Thu, 27 Apr 2017 17:01:08 -0700
Subject: [PATCH 19/20] Fix setIntersection to account for edge case

---
 .babelrc                       |  2 +-
 src/setIntersection.js         | 21 +++++++++++++++------
 test/collatzConjecture_test.js |  1 +
 test/setIntersection_test.js   |  1 +
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/.babelrc b/.babelrc
index 2f01e1d..002b4aa 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,3 +1,3 @@
 {
   "presets": ["env"]
-}
\ No newline at end of file
+}
diff --git a/src/setIntersection.js b/src/setIntersection.js
index a5a1118..3201e1c 100644
--- a/src/setIntersection.js
+++ b/src/setIntersection.js
@@ -8,16 +8,25 @@
 // // => [2, 4]
 
 
-export default function setIntersection(a, b){
-  if ( !Array.isArray(a) || !Array.isArray(b) ) {
+export default function setIntersection(setA, setB) {
+  if ( !Array.isArray(setA) || !Array.isArray(setB) ) {
     throw new Error('Invalid input format. Expected two arrays')
   }
-  let concatArr = a.concat(b)
-  let sortedArr = concatArr.sort()
+  let complementArray = []
 
+  for(let element of setB) {
+    if(setA.includes(element)) {
+      complementArray.push(element)
+    }
+  }
+  for(let element of setA){
+    if(setB.includes(element)) {
+      complementArray.push(element)
+    }
+  }
   function isDuplicate(value, index, array){
     return array.indexOf(value) !== index
   }
-  let filteredArr = sortedArr.filter(isDuplicate)
-  return filteredArr
+  let filteredArr = complementArray.filter(isDuplicate)
+  return filteredArr.sort()
 }
diff --git a/test/collatzConjecture_test.js b/test/collatzConjecture_test.js
index c895ca0..62674f2 100644
--- a/test/collatzConjecture_test.js
+++ b/test/collatzConjecture_test.js
@@ -6,6 +6,7 @@ describe('collatzConjecture()', function(){
   it('should be a function', function(){
     expect(collatzConjecture).to.be.a('function')
   })
+  
   it('returns a Collatz sequence for any positive integer', function(){
     expect(collatzConjecture(7)).to.eql([7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1])
     expect(collatzConjecture(3)).to.eql([3, 10, 5, 16, 8, 4, 2, 1])
diff --git a/test/setIntersection_test.js b/test/setIntersection_test.js
index 871a6a0..5a76ef5 100644
--- a/test/setIntersection_test.js
+++ b/test/setIntersection_test.js
@@ -10,6 +10,7 @@ describe('setIntersection', function(){
   it('returns the intersection of two sets', function () {
     expect(setIntersection([1, 2, 3, 4],[2, 4, 6, 8])).to.eql([2,4])
     expect(setIntersection([82,90,1], [1, 2, 90])).to.eql([1,90])
+    expect(setIntersection([1,1,2,3,4], [2,4,6,8])).to.eql([2,4])
   })
 
   it('throws an error when given invalid inputs', function() {

From 61634618b5c55ea19ceceaff5e5b3142fa68f276 Mon Sep 17 00:00:00 2001
From: SomayaB <somaya.bounouar@gmail.com>
Date: Thu, 27 Apr 2017 17:17:21 -0700
Subject: [PATCH 20/20] Refactor to ES6

---
 src/collatzConjecture.js            |  4 +++-
 src/factorial.js                    |  8 +++++---
 src/fibonacci.js                    | 14 ++++++++------
 src/fizzBuzz.js                     |  6 ++++--
 src/isPalindrome.js                 | 20 +++++++++++---------
 src/makeChange.js                   |  4 +++-
 src/setComplement.js                |  4 +++-
 src/setIntersection.js              |  4 +++-
 src/setSymmetricDifference.js       |  4 ++--
 src/setUnion.js                     |  4 +++-
 test/collatzConjecture_test.js      |  4 ++--
 test/factorial_test.js              |  2 +-
 test/fibonacci_test.js              |  2 +-
 test/fizzBuzz_test.js               |  2 +-
 test/isPalindrome_test.js           |  2 +-
 test/makeChange_test.js             |  2 +-
 test/setComplement_test.js          |  2 +-
 test/setIntersection_test.js        |  2 +-
 test/setSymmetricDifference_test.js |  4 ++--
 test/setUnion_test.js               |  2 +-
 20 files changed, 57 insertions(+), 39 deletions(-)

diff --git a/src/collatzConjecture.js b/src/collatzConjecture.js
index 3f5a5e1..e4c8348 100644
--- a/src/collatzConjecture.js
+++ b/src/collatzConjecture.js
@@ -12,7 +12,7 @@
 // // => [7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1]
 
 
-export default function collatzConjecture(num) {
+let collatzConjecture = num => {
   if (!Number.isInteger(num) || num < 0) {
     throw new Error('Invalid input format. Expected a positive integer')
   }
@@ -30,3 +30,5 @@ export default function collatzConjecture(num) {
   }
   return collatzArr
 }
+
+module.exports = { collatzConjecture }
diff --git a/src/factorial.js b/src/factorial.js
index 20ff181..867ed5e 100644
--- a/src/factorial.js
+++ b/src/factorial.js
@@ -5,14 +5,16 @@
 // factorial(5)
 // // => 120
 
-export default function factorial(num) {
-  var accumulator = num
-  for (var i = num; i > 1; i--) {
+let factorial = num => {
+  let accumulator = num
+  for (let i = num; i > 1; i--) {
     accumulator = accumulator * (i - 1)
   }
   return accumulator
 }
 
+module.exports = { factorial }
+
 //Other way:
 //   var factorialElements = [num]
 //   for (var i = num; i > 1; i--) {
diff --git a/src/fibonacci.js b/src/fibonacci.js
index 88a9a4a..8c17b2f 100644
--- a/src/fibonacci.js
+++ b/src/fibonacci.js
@@ -5,16 +5,16 @@
 // fibonacci(10)
 // // => [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
 
-export default function fibonacci(num) {
+let fibonacci = num => {
   if (typeof num !== 'number') {
     throw new Error('Invalid input format. Expected a number')
   }
-  var first = 0
-  var second = 1
-  var result
-  var fibonacciArr = [0]
+  let first = 0
+  let second = 1
+  let result
+  let fibonacciArr = [0]
 
-  for (var i = 1; i < num; i++) {
+  for (let i = 1; i < num; i++) {
     result = first + second
     first = second
     second = result
@@ -22,3 +22,5 @@ export default function fibonacci(num) {
   }
   return fibonacciArr
 }
+
+module.exports = { fibonacci }
diff --git a/src/fizzBuzz.js b/src/fizzBuzz.js
index e32601a..17922e7 100644
--- a/src/fizzBuzz.js
+++ b/src/fizzBuzz.js
@@ -9,9 +9,9 @@
 // fizzBuzz()
 // // => [1, 2, 'Fizz', 4, 'Buzz', 'Fizz', 7, 8, 'Fizz', 'Buzz', 11, 'Fizz', 13, 14, 'FizzBuzz', ...]
 
-export default function fizzBuzz() {
+let fizzBuzz = () => {
   let fizzBuzzArray = []
-  for (var i = 1; i <= 100; i++){
+  for (let i = 1; i <= 100; i++){
     if (i % 3 == 0 && i % 5 == 0) {
       fizzBuzzArray.push('FizzBuzz')
     } else if (i % 3 == 0) {
@@ -24,3 +24,5 @@ export default function fizzBuzz() {
   }
   return fizzBuzzArray
 }
+
+module.exports = { fizzBuzz }
diff --git a/src/isPalindrome.js b/src/isPalindrome.js
index 714cee7..2008062 100644
--- a/src/isPalindrome.js
+++ b/src/isPalindrome.js
@@ -13,20 +13,20 @@
 // isPalindrome('A man, a plan, a canal: Panama')
 // // => true
 
-export default function isPalindrome(string) {
-  var strToLowerCase = string.toLowerCase()
-  var cleanStr = strToLowerCase.replace(/[^a-zA-Z]/g, '')
-  var isPalindromeArray = cleanStr.split('')
+let isPalindrome = string => {
+  let strToLowerCase = string.toLowerCase()
+  let cleanStr = strToLowerCase.replace(/[^a-zA-Z]/g, '')
+  let isPalindromeArray = cleanStr.split('')
 
-  var shiftArray = []
-  var popArray = []
+  let shiftArray = []
+  let popArray = []
 
-  for (var i = 0; i < isPalindromeArray.length; i++) {
+  for (let i = 0; i < isPalindromeArray.length; i++) {
     shiftArray.push(isPalindromeArray.shift([i]))
     popArray.push(isPalindromeArray.pop([i]))
   }
-  var shiftString = shiftArray.join('')
-  var popString = popArray.join('')
+  let shiftString = shiftArray.join('')
+  let popString = popArray.join('')
 
   if (shiftString == popString) {
     return true
@@ -34,3 +34,5 @@ export default function isPalindrome(string) {
     return false
   }
 }
+
+module.exports = { isPalindrome }
diff --git a/src/makeChange.js b/src/makeChange.js
index 6269a1b..ae6e03d 100644
--- a/src/makeChange.js
+++ b/src/makeChange.js
@@ -14,7 +14,7 @@
 // // => { quarters: 2, dimes: 1, nickels: 1, pennies: 3 }
 
 
-export default function makeChange(options) {
+let makeChange = options => {
   if (typeof options !== 'object') {
     throw new Error('Invalid input format. Expected an object')
   }
@@ -48,3 +48,5 @@ export default function makeChange(options) {
   }
   return change
 }
+
+module.exports = { makeChange }
diff --git a/src/setComplement.js b/src/setComplement.js
index 75210b3..fc30fbd 100644
--- a/src/setComplement.js
+++ b/src/setComplement.js
@@ -8,7 +8,7 @@
 // // => [6, 8]
 
 
-export default function setComplement(setA, setB) {
+let setComplement = (setA, setB) => {
   if ( !Array.isArray(setA) || !Array.isArray(setB) ) {
     throw new Error('Invalid input format. Expected two arrays')
   }
@@ -20,3 +20,5 @@ export default function setComplement(setA, setB) {
   }
   return complementArray
 }
+
+module.exports = { setComplement }
diff --git a/src/setIntersection.js b/src/setIntersection.js
index 3201e1c..b655c49 100644
--- a/src/setIntersection.js
+++ b/src/setIntersection.js
@@ -8,7 +8,7 @@
 // // => [2, 4]
 
 
-export default function setIntersection(setA, setB) {
+let setIntersection = (setA, setB) => {
   if ( !Array.isArray(setA) || !Array.isArray(setB) ) {
     throw new Error('Invalid input format. Expected two arrays')
   }
@@ -30,3 +30,5 @@ export default function setIntersection(setA, setB) {
   let filteredArr = complementArray.filter(isDuplicate)
   return filteredArr.sort()
 }
+
+module.exports = { setIntersection }
diff --git a/src/setSymmetricDifference.js b/src/setSymmetricDifference.js
index 6db53a9..2384ff6 100644
--- a/src/setSymmetricDifference.js
+++ b/src/setSymmetricDifference.js
@@ -8,7 +8,7 @@
 // // => [1, 3, 6, 8]
 
 
-export default function setSymmetricDifference(setA, setB) {
+let setSymmetricDifference = (setA, setB) => {
   if ( !Array.isArray(setA) || !Array.isArray(setB) ) {
     throw new Error('Invalid input format. Expected two arrays')
   }
@@ -27,4 +27,4 @@ export default function setSymmetricDifference(setA, setB) {
   return complementArray.sort()
 }
 
-//
+module.exports = { setSymmetricDifference }
diff --git a/src/setUnion.js b/src/setUnion.js
index 79f5b94..350e7db 100644
--- a/src/setUnion.js
+++ b/src/setUnion.js
@@ -7,7 +7,7 @@
 // setUnion(a, b)
 // // => [1, 2, 3, 4, 6, 8]
 
-export default function setUnion(a, b){
+let setUnion = (a, b) => {
   if (!Array.isArray(a) || !Array.isArray(b)){
     throw new Error('Invalid input format. Expected two arrays')
   }
@@ -20,3 +20,5 @@ export default function setUnion(a, b){
   let filteredArr = sortedArr.filter(isUnique)
   return filteredArr
 }
+
+module.exports = { setUnion }
diff --git a/test/collatzConjecture_test.js b/test/collatzConjecture_test.js
index 62674f2..4149886 100644
--- a/test/collatzConjecture_test.js
+++ b/test/collatzConjecture_test.js
@@ -1,12 +1,12 @@
 import { expect } from 'chai'
-import collatzConjecture from '../src/collatzConjecture'
+import { collatzConjecture } from '../src/collatzConjecture'
 
 describe('collatzConjecture()', function(){
 
   it('should be a function', function(){
     expect(collatzConjecture).to.be.a('function')
   })
-  
+
   it('returns a Collatz sequence for any positive integer', function(){
     expect(collatzConjecture(7)).to.eql([7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1])
     expect(collatzConjecture(3)).to.eql([3, 10, 5, 16, 8, 4, 2, 1])
diff --git a/test/factorial_test.js b/test/factorial_test.js
index 12daa9e..ef9b7d6 100644
--- a/test/factorial_test.js
+++ b/test/factorial_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import factorial from '../src/factorial'
+import { factorial } from '../src/factorial'
 
 describe('factorial()', function(){
 
diff --git a/test/fibonacci_test.js b/test/fibonacci_test.js
index 06154f6..6c9c221 100644
--- a/test/fibonacci_test.js
+++ b/test/fibonacci_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import fibonacci from '../src/fibonacci'
+import { fibonacci } from '../src/fibonacci'
 
 describe ('fibonacci', function(){
 
diff --git a/test/fizzBuzz_test.js b/test/fizzBuzz_test.js
index befb983..ff58373 100644
--- a/test/fizzBuzz_test.js
+++ b/test/fizzBuzz_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import fizzBuzz from '../src/fizzBuzz'
+import { fizzBuzz } from '../src/fizzBuzz'
 
 describe('fizzBuzz()', function(){
 
diff --git a/test/isPalindrome_test.js b/test/isPalindrome_test.js
index 0b224f7..70c2d77 100644
--- a/test/isPalindrome_test.js
+++ b/test/isPalindrome_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import isPalindrome from '../src/isPalindrome'
+import { isPalindrome } from '../src/isPalindrome'
 
 describe('isPalindrome', function() {
 
diff --git a/test/makeChange_test.js b/test/makeChange_test.js
index 9956816..e512241 100644
--- a/test/makeChange_test.js
+++ b/test/makeChange_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import makeChange from '../src/makeChange'
+import { makeChange } from '../src/makeChange'
 
 describe('makeChange()', function(){
 
diff --git a/test/setComplement_test.js b/test/setComplement_test.js
index a8159ec..c3e7121 100644
--- a/test/setComplement_test.js
+++ b/test/setComplement_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import setComplement from '../src/setComplement'
+import { setComplement } from '../src/setComplement'
 
 describe('setComplement', function(){
 
diff --git a/test/setIntersection_test.js b/test/setIntersection_test.js
index 5a76ef5..383836a 100644
--- a/test/setIntersection_test.js
+++ b/test/setIntersection_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import setIntersection from '../src/setIntersection'
+import { setIntersection } from '../src/setIntersection'
 
 describe('setIntersection', function(){
 
diff --git a/test/setSymmetricDifference_test.js b/test/setSymmetricDifference_test.js
index 11f9554..c52a57e 100644
--- a/test/setSymmetricDifference_test.js
+++ b/test/setSymmetricDifference_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import setSymmetricDifference from '../src/setSymmetricDifference'
+import { setSymmetricDifference } from '../src/setSymmetricDifference'
 
 
 
@@ -12,7 +12,7 @@ describe('setSymmetricDifference', function() {
   it('returns the symmetric difference of two sets', function() {
     expect(setSymmetricDifference([1, 2, 3, 4], [2, 4, 6, 8])).to.eql([1, 3, 6, 8])
   })
-  
+
   it('throws an error when given invalid inputs', function() {
     expect(function() {setSymmetricDifference('string', [1,2])}).
     to.throw('Invalid input format. Expected two arrays')
diff --git a/test/setUnion_test.js b/test/setUnion_test.js
index 154031e..74f7ef9 100644
--- a/test/setUnion_test.js
+++ b/test/setUnion_test.js
@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import setUnion from '../src/setUnion'
+import { setUnion } from '../src/setUnion'
 
 describe('setUnion', function(){