From ed7975aeb23bf8d48d9495905774177b521e28f9 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 18:34:29 +0000
Subject: [PATCH 01/18] feat| create spec files

---
 13_factorial/factorial.spec.js                | 40 +++++++++++++++++++
 .../solution/factorial-solution.spec.js       | 40 +++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 13_factorial/factorial.spec.js
 create mode 100644 13_factorial/solution/factorial-solution.spec.js

diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
new file mode 100644
index 00000000000..47be4957aa4
--- /dev/null
+++ b/13_factorial/factorial.spec.js
@@ -0,0 +1,40 @@
+const factorial = require("./factorial");
+
+describe('factorial', () => {
+  test('4th factorial number is 24', () => {
+    expect(factorial(4)).toBe(24);
+  });
+  test.skip('6th factorial number is 720', () => {
+    expect(factorial(6)).toBe(720);
+  });
+  test.skip('10th factorial number is 3628800', () => {
+    expect(factorial(10)).toBe(3628800);
+  });
+  test.skip('15th factorial number is 1.3076744e+12', () => {
+    expect(factorial(15)).toBe(1.3076744e12);
+  });
+  test.skip('25th factorial number is 1.551121e+25', () => {
+    expect(factorial(25)).toBe(1.551121e25);
+  });
+  test.skip('0th factorial number is 1', () => {
+    expect(factorial(0)).toBe(1);
+  });
+  test.skip('doesn\'t accept negatives', () => {
+    expect(factorial(-25)).toBe(undefined);
+  });
+  test.skip('doesn\'t accept floats', () => {
+    expect(factorial(5.4)).toBe(undefined);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("0")).toBe(1);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("1")).toBe(1);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("2")).toBe(2);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("8")).toBe(40320);
+  });
+});
diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
new file mode 100644
index 00000000000..527dcccbc74
--- /dev/null
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -0,0 +1,40 @@
+const factorial = require("./factorial-solution");
+
+describe('factorial', () => {
+  test('4th factorial number is 24', () => {
+    expect(factorial(4)).toBe(24);
+  });
+  test.skip('6th factorial number is 720', () => {
+    expect(factorial(6)).toBe(720);
+  });
+  test.skip('10th factorial number is 3628800', () => {
+    expect(factorial(10)).toBe(3628800);
+  });
+  test.skip('15th factorial number is 1.3076744e+12', () => {
+    expect(factorial(15)).toBe(1.3076744e12);
+  });
+  test.skip('25th factorial number is 1.551121e+25', () => {
+    expect(factorial(25)).toBe(1.551121e25);
+  });
+  test.skip('0th factorial number is 1', () => {
+    expect(factorial(0)).toBe(1);
+  });
+  test.skip('doesn\'t accept negatives', () => {
+    expect(factorial(-25)).toBe(undefined);
+  });
+  test.skip('doesn\'t accept floats', () => {
+    expect(factorial(5.4)).toBe(undefined);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("0")).toBe(1);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("1")).toBe(1);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("2")).toBe(2);
+  });
+  test.skip('DOES accept strings', () => {
+    expect(factorial("8")).toBe(40320);
+  });
+});

From 8845572e60eab5362e741fc405f55a9ef6ed4d30 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 18:35:25 +0000
Subject: [PATCH 02/18] feat| create readme

---
 13_factorial/README.md | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 13_factorial/README.md

diff --git a/13_factorial/README.md b/13_factorial/README.md
new file mode 100644
index 00000000000..becd7d526da
--- /dev/null
+++ b/13_factorial/README.md
@@ -0,0 +1,13 @@
+# Exercise 13 - Factorial
+
+Create a function that takes an input integer greater than or equal to 1 and returns the product of all its predecessing integers. If 0 is input it returns 1. It should accept strings that when converted to a number are valid inputs. For invalid inputs it returns `undefined`.
+
+For example:
+
+```javascript
+factorial(2); // 2 * 1, Output: 2
+factorial('4'); // 4 * 3 * 2 * 1, Output: 24
+factorial(5); // 5 * 4 * 3 * 2 * 1, Output: 120
+factorial(7.2); // Output: undefined
+factorial(0); // Output: 1
+```

From 670d85ea6a92ad26feb014e5a28e4b2658384560 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 18:36:50 +0000
Subject: [PATCH 03/18] feat| create solution files

---
 13_factorial/factorial.js                   | 6 ++++++
 13_factorial/solution/factorial-solution.js | 8 ++++++++
 2 files changed, 14 insertions(+)
 create mode 100644 13_factorial/factorial.js
 create mode 100644 13_factorial/solution/factorial-solution.js

diff --git a/13_factorial/factorial.js b/13_factorial/factorial.js
new file mode 100644
index 00000000000..a88e4f6e573
--- /dev/null
+++ b/13_factorial/factorial.js
@@ -0,0 +1,6 @@
+const factorial = function() {
+
+};
+
+// Do not edit below this line
+module.exports = factorial;
\ No newline at end of file
diff --git a/13_factorial/solution/factorial-solution.js b/13_factorial/solution/factorial-solution.js
new file mode 100644
index 00000000000..62dcaf2fc6b
--- /dev/null
+++ b/13_factorial/solution/factorial-solution.js
@@ -0,0 +1,8 @@
+const factorial = function(n) {
+  if (/[.-]/.match(n + '')) return;
+  if (n === 0 || n === 1) return 1;
+  return factorial(n - 1) + factorial(n - 2);
+};
+
+// Do not edit below this line
+module.exports = factorial;
\ No newline at end of file

From 4d4603191424613e8008c9c687a24d414ee41fa7 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 18:57:34 +0000
Subject: [PATCH 04/18] fix| factorial solution now passes

---
 13_factorial/solution/factorial-solution.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/13_factorial/solution/factorial-solution.js b/13_factorial/solution/factorial-solution.js
index 62dcaf2fc6b..d0f5e42a361 100644
--- a/13_factorial/solution/factorial-solution.js
+++ b/13_factorial/solution/factorial-solution.js
@@ -1,7 +1,7 @@
 const factorial = function(n) {
-  if (/[.-]/.match(n + '')) return;
-  if (n === 0 || n === 1) return 1;
-  return factorial(n - 1) + factorial(n - 2);
+  if (/[-.]/.test(n + '')) return;
+  if (+n === 0 || +n === 1) return 1;
+  return n * factorial(n - 1);
 };
 
 // Do not edit below this line

From ee05ca925aa60a5472f4f15bd1c75e30ae428197 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 18:58:48 +0000
Subject: [PATCH 05/18] feat| spec file fixed

---
 .../solution/factorial-solution.spec.js       | 26 +++++++++----------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
index 527dcccbc74..ec5ab50c31a 100644
--- a/13_factorial/solution/factorial-solution.spec.js
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -4,37 +4,37 @@ describe('factorial', () => {
   test('4th factorial number is 24', () => {
     expect(factorial(4)).toBe(24);
   });
-  test.skip('6th factorial number is 720', () => {
+  test('6th factorial number is 720', () => {
     expect(factorial(6)).toBe(720);
   });
-  test.skip('10th factorial number is 3628800', () => {
+  test('10th factorial number is 3628800', () => {
     expect(factorial(10)).toBe(3628800);
   });
-  test.skip('15th factorial number is 1.3076744e+12', () => {
-    expect(factorial(15)).toBe(1.3076744e12);
+  test('15th factorial number is 1307674368000', () => {
+    expect(factorial(15)).toBe(1307674368000);
   });
-  test.skip('25th factorial number is 1.551121e+25', () => {
-    expect(factorial(25)).toBe(1.551121e25);
+  test('25th factorial number is 1.5511210043330986e+255', () => {
+    expect(factorial(25)).toBe(1.5511210043330986e+25);
   });
-  test.skip('0th factorial number is 1', () => {
+  test('0th factorial number is 1', () => {
     expect(factorial(0)).toBe(1);
   });
-  test.skip('doesn\'t accept negatives', () => {
+  test('doesn\'t accept negatives', () => {
     expect(factorial(-25)).toBe(undefined);
   });
-  test.skip('doesn\'t accept floats', () => {
+  test('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('DOES accept strings', () => {
+  test('DOES accept strings', () => {
     expect(factorial("0")).toBe(1);
   });
-  test.skip('DOES accept strings', () => {
+  test('DOES accept strings', () => {
     expect(factorial("1")).toBe(1);
   });
-  test.skip('DOES accept strings', () => {
+  test('DOES accept strings', () => {
     expect(factorial("2")).toBe(2);
   });
-  test.skip('DOES accept strings', () => {
+  test('DOES accept strings', () => {
     expect(factorial("8")).toBe(40320);
   });
 });

From f3174925119eac97115ff64b3ede1d3fbdc548e8 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 19:01:21 +0000
Subject: [PATCH 06/18] fix| spec

---
 13_factorial/factorial.spec.js                | 10 ++++-----
 .../solution/factorial-solution.spec.js       | 22 +++++++++----------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
index 47be4957aa4..95f97dd1eb5 100644
--- a/13_factorial/factorial.spec.js
+++ b/13_factorial/factorial.spec.js
@@ -1,4 +1,4 @@
-const factorial = require("./factorial");
+const factorial = require("./factorial-solution");
 
 describe('factorial', () => {
   test('4th factorial number is 24', () => {
@@ -10,11 +10,11 @@ describe('factorial', () => {
   test.skip('10th factorial number is 3628800', () => {
     expect(factorial(10)).toBe(3628800);
   });
-  test.skip('15th factorial number is 1.3076744e+12', () => {
-    expect(factorial(15)).toBe(1.3076744e12);
+  test.skip('15th factorial number is 1307674368000', () => {
+    expect(factorial(15)).toBe(1307674368000);
   });
-  test.skip('25th factorial number is 1.551121e+25', () => {
-    expect(factorial(25)).toBe(1.551121e25);
+  test.skip('25th factorial number is 1.5511210043330986e+255', () => {
+    expect(factorial(25)).toBe(1.5511210043330986e+25);
   });
   test.skip('0th factorial number is 1', () => {
     expect(factorial(0)).toBe(1);
diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
index ec5ab50c31a..95f97dd1eb5 100644
--- a/13_factorial/solution/factorial-solution.spec.js
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -4,37 +4,37 @@ describe('factorial', () => {
   test('4th factorial number is 24', () => {
     expect(factorial(4)).toBe(24);
   });
-  test('6th factorial number is 720', () => {
+  test.skip('6th factorial number is 720', () => {
     expect(factorial(6)).toBe(720);
   });
-  test('10th factorial number is 3628800', () => {
+  test.skip('10th factorial number is 3628800', () => {
     expect(factorial(10)).toBe(3628800);
   });
-  test('15th factorial number is 1307674368000', () => {
+  test.skip('15th factorial number is 1307674368000', () => {
     expect(factorial(15)).toBe(1307674368000);
   });
-  test('25th factorial number is 1.5511210043330986e+255', () => {
+  test.skip('25th factorial number is 1.5511210043330986e+255', () => {
     expect(factorial(25)).toBe(1.5511210043330986e+25);
   });
-  test('0th factorial number is 1', () => {
+  test.skip('0th factorial number is 1', () => {
     expect(factorial(0)).toBe(1);
   });
-  test('doesn\'t accept negatives', () => {
+  test.skip('doesn\'t accept negatives', () => {
     expect(factorial(-25)).toBe(undefined);
   });
-  test('doesn\'t accept floats', () => {
+  test.skip('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test('DOES accept strings', () => {
+  test.skip('DOES accept strings', () => {
     expect(factorial("0")).toBe(1);
   });
-  test('DOES accept strings', () => {
+  test.skip('DOES accept strings', () => {
     expect(factorial("1")).toBe(1);
   });
-  test('DOES accept strings', () => {
+  test.skip('DOES accept strings', () => {
     expect(factorial("2")).toBe(2);
   });
-  test('DOES accept strings', () => {
+  test.skip('DOES accept strings', () => {
     expect(factorial("8")).toBe(40320);
   });
 });

From 3530f26329f2bf61411902e539eda0dcb165c23e Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 19:25:10 +0000
Subject: [PATCH 07/18] feat/ add comments

---
 13_factorial/factorial.spec.js                   | 2 +-
 13_factorial/solution/factorial-solution.js      | 6 ++++++
 13_factorial/solution/factorial-solution.spec.js | 2 +-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
index 95f97dd1eb5..7794d091d6a 100644
--- a/13_factorial/factorial.spec.js
+++ b/13_factorial/factorial.spec.js
@@ -13,7 +13,7 @@ describe('factorial', () => {
   test.skip('15th factorial number is 1307674368000', () => {
     expect(factorial(15)).toBe(1307674368000);
   });
-  test.skip('25th factorial number is 1.5511210043330986e+255', () => {
+  test.skip('25th factorial number is 1.5511210043330986e+25', () => {
     expect(factorial(25)).toBe(1.5511210043330986e+25);
   });
   test.skip('0th factorial number is 1', () => {
diff --git a/13_factorial/solution/factorial-solution.js b/13_factorial/solution/factorial-solution.js
index d0f5e42a361..9cf4397b8b4 100644
--- a/13_factorial/solution/factorial-solution.js
+++ b/13_factorial/solution/factorial-solution.js
@@ -1,5 +1,11 @@
 const factorial = function(n) {
+  // a negative number will always contain a '-'
+  // a non-integer will always contain a '.'
+  // the [-.] regex literal will match strings that contain a '-' or a '.'
+  // n + '' converts n to a string, which is required for the Regex.prototype.test method 
   if (/[-.]/.test(n + '')) return;
+
+  // +n converts n to a number
   if (+n === 0 || +n === 1) return 1;
   return n * factorial(n - 1);
 };
diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
index 95f97dd1eb5..7794d091d6a 100644
--- a/13_factorial/solution/factorial-solution.spec.js
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -13,7 +13,7 @@ describe('factorial', () => {
   test.skip('15th factorial number is 1307674368000', () => {
     expect(factorial(15)).toBe(1307674368000);
   });
-  test.skip('25th factorial number is 1.5511210043330986e+255', () => {
+  test.skip('25th factorial number is 1.5511210043330986e+25', () => {
     expect(factorial(25)).toBe(1.5511210043330986e+25);
   });
   test.skip('0th factorial number is 1', () => {

From 6c72df864b2db11c2ce49cf91742b6376fc03775 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Fri, 22 Mar 2024 19:38:28 +0000
Subject: [PATCH 08/18] fix/ refactor

---
 13_factorial/solution/factorial-solution.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/13_factorial/solution/factorial-solution.js b/13_factorial/solution/factorial-solution.js
index 9cf4397b8b4..0478c3953fd 100644
--- a/13_factorial/solution/factorial-solution.js
+++ b/13_factorial/solution/factorial-solution.js
@@ -6,9 +6,9 @@ const factorial = function(n) {
   if (/[-.]/.test(n + '')) return;
 
   // +n converts n to a number
-  if (+n === 0 || +n === 1) return 1;
+  if (+n === 0) return 1;
   return n * factorial(n - 1);
 };
 
 // Do not edit below this line
-module.exports = factorial;
\ No newline at end of file
+module.exports = factorial;

From dc40770f140edc528e734a73afa4b2c22c846516 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 10:54:41 +0000
Subject: [PATCH 09/18] feat/ improve wording

Co-authored-by: MaoShizhong <122839503+MaoShizhong@users.noreply.github.com>
---
 13_factorial/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/13_factorial/README.md b/13_factorial/README.md
index becd7d526da..8b4a077faaa 100644
--- a/13_factorial/README.md
+++ b/13_factorial/README.md
@@ -1,6 +1,6 @@
 # Exercise 13 - Factorial
 
-Create a function that takes an input integer greater than or equal to 1 and returns the product of all its predecessing integers. If 0 is input it returns 1. It should accept strings that when converted to a number are valid inputs. For invalid inputs it returns `undefined`.
+Write a recursive function that takes a non-negative integer, and returns the product of all positive integers less than or equal to the input integer. An input of `0` should return `1`. The function should only accept numbers, so `'4'` should not be accepted as it is a string. All invalid inputs should return `undefined`.
 
 For example:
 

From 882d418eb80203175acf08ded4571d61c17e95fa Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 12:04:16 +0000
Subject: [PATCH 10/18] feat/ update function to not accept strings

---
 13_factorial/README.md                           |  3 +--
 13_factorial/factorial.spec.js                   | 13 ++-----------
 13_factorial/solution/factorial-solution.js      | 10 ++--------
 13_factorial/solution/factorial-solution.spec.js | 13 ++-----------
 4 files changed, 7 insertions(+), 32 deletions(-)

diff --git a/13_factorial/README.md b/13_factorial/README.md
index 8b4a077faaa..b1f20df08eb 100644
--- a/13_factorial/README.md
+++ b/13_factorial/README.md
@@ -5,8 +5,7 @@ Write a recursive function that takes a non-negative integer, and returns the pr
 For example:
 
 ```javascript
-factorial(2); // 2 * 1, Output: 2
-factorial('4'); // 4 * 3 * 2 * 1, Output: 24
+factorial('4'); // Output: undefined
 factorial(5); // 5 * 4 * 3 * 2 * 1, Output: 120
 factorial(7.2); // Output: undefined
 factorial(0); // Output: 1
diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
index 7794d091d6a..eddcb478ac9 100644
--- a/13_factorial/factorial.spec.js
+++ b/13_factorial/factorial.spec.js
@@ -25,16 +25,7 @@ describe('factorial', () => {
   test.skip('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("0")).toBe(1);
-  });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("1")).toBe(1);
-  });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("2")).toBe(2);
-  });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("8")).toBe(40320);
+  test.skip('doesn\'t accept strings', () => {
+    expect(factorial('5')).toBe(undefined);
   });
 });
diff --git a/13_factorial/solution/factorial-solution.js b/13_factorial/solution/factorial-solution.js
index 0478c3953fd..2525458b88b 100644
--- a/13_factorial/solution/factorial-solution.js
+++ b/13_factorial/solution/factorial-solution.js
@@ -1,12 +1,6 @@
 const factorial = function(n) {
-  // a negative number will always contain a '-'
-  // a non-integer will always contain a '.'
-  // the [-.] regex literal will match strings that contain a '-' or a '.'
-  // n + '' converts n to a string, which is required for the Regex.prototype.test method 
-  if (/[-.]/.test(n + '')) return;
-
-  // +n converts n to a number
-  if (+n === 0) return 1;
+  if (!Number.isInteger(n) || n < 0) return;
+  if (n === 0) return 1;
   return n * factorial(n - 1);
 };
 
diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
index 7794d091d6a..eddcb478ac9 100644
--- a/13_factorial/solution/factorial-solution.spec.js
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -25,16 +25,7 @@ describe('factorial', () => {
   test.skip('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("0")).toBe(1);
-  });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("1")).toBe(1);
-  });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("2")).toBe(2);
-  });
-  test.skip('DOES accept strings', () => {
-    expect(factorial("8")).toBe(40320);
+  test.skip('doesn\'t accept strings', () => {
+    expect(factorial('5')).toBe(undefined);
   });
 });

From 052637d71eb4937a90c49d7f9d1406966e726cc8 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 12:12:30 +0000
Subject: [PATCH 11/18] feat/ remove comment

---
 13_factorial/solution/factorial-solution.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/13_factorial/solution/factorial-solution.js b/13_factorial/solution/factorial-solution.js
index 2525458b88b..f28cc71b445 100644
--- a/13_factorial/solution/factorial-solution.js
+++ b/13_factorial/solution/factorial-solution.js
@@ -4,5 +4,4 @@ const factorial = function(n) {
   return n * factorial(n - 1);
 };
 
-// Do not edit below this line
 module.exports = factorial;

From eaabc5ba1442c70af3bce3ed62b0eb0414343775 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 13:11:17 +0000
Subject: [PATCH 12/18] feat/ improve order

Co-authored-by: MaoShizhong <122839503+MaoShizhong@users.noreply.github.com>
---
 13_factorial/README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/13_factorial/README.md b/13_factorial/README.md
index b1f20df08eb..847ba3fe8c5 100644
--- a/13_factorial/README.md
+++ b/13_factorial/README.md
@@ -5,8 +5,8 @@ Write a recursive function that takes a non-negative integer, and returns the pr
 For example:
 
 ```javascript
-factorial('4'); // Output: undefined
 factorial(5); // 5 * 4 * 3 * 2 * 1, Output: 120
-factorial(7.2); // Output: undefined
 factorial(0); // Output: 1
+factorial(7.2); // Output: undefined
+factorial('4'); // Output: undefined
 ```

From 3bc04827e37b09bb41a722a6617bb0b4d43c0f60 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 14:30:53 +0000
Subject: [PATCH 13/18] feat/ remove unnecesary describe

---
 13_factorial/factorial.spec.js                   | 8 +++++++-
 13_factorial/solution/factorial-solution.spec.js | 8 +++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
index eddcb478ac9..35c18e8b49c 100644
--- a/13_factorial/factorial.spec.js
+++ b/13_factorial/factorial.spec.js
@@ -25,7 +25,13 @@ describe('factorial', () => {
   test.skip('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('doesn\'t accept strings', () => {
+  test.skip('doesn\'t accept a number as a string', () => {
     expect(factorial('5')).toBe(undefined);
   });
+  test.skip('doesn\'t accept strings', () => {
+    expect(factorial('foo')).toBe(undefined);
+  });
+  test.skip('doesn\'t accept arrays', () => {
+    expect(factorial([5])).toBe(undefined);
+  });
 });
diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
index eddcb478ac9..35c18e8b49c 100644
--- a/13_factorial/solution/factorial-solution.spec.js
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -25,7 +25,13 @@ describe('factorial', () => {
   test.skip('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('doesn\'t accept strings', () => {
+  test.skip('doesn\'t accept a number as a string', () => {
     expect(factorial('5')).toBe(undefined);
   });
+  test.skip('doesn\'t accept strings', () => {
+    expect(factorial('foo')).toBe(undefined);
+  });
+  test.skip('doesn\'t accept arrays', () => {
+    expect(factorial([5])).toBe(undefined);
+  });
 });

From ab1e7285deb7df3d86499ca26a3d166d3f9f8456 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 16:46:00 +0000
Subject: [PATCH 14/18] feat/ single quotes replaced with double quotes

---
 13_factorial/factorial.spec.js | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
index 35c18e8b49c..a079053b572 100644
--- a/13_factorial/factorial.spec.js
+++ b/13_factorial/factorial.spec.js
@@ -19,19 +19,19 @@ describe('factorial', () => {
   test.skip('0th factorial number is 1', () => {
     expect(factorial(0)).toBe(1);
   });
-  test.skip('doesn\'t accept negatives', () => {
+  test.skip("doesn't accept negatives", () => {
     expect(factorial(-25)).toBe(undefined);
   });
-  test.skip('doesn\'t accept floats', () => {
+  test.skip("doesn't accept floats", () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('doesn\'t accept a number as a string', () => {
+  test.skip("doesn't accept a number as a string", () => {
     expect(factorial('5')).toBe(undefined);
   });
-  test.skip('doesn\'t accept strings', () => {
+  test.skip("doesn't accept strings", () => {
     expect(factorial('foo')).toBe(undefined);
   });
-  test.skip('doesn\'t accept arrays', () => {
+  test.skip("doesn't accept arrays", () => {
     expect(factorial([5])).toBe(undefined);
   });
 });

From f1f29ac500be711682bb8a16fd04b5d3dc5b53b5 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 16:48:50 +0000
Subject: [PATCH 15/18] feat/ add wikipedia link to factorial

---
 13_factorial/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/13_factorial/README.md b/13_factorial/README.md
index 847ba3fe8c5..17831cbd7b3 100644
--- a/13_factorial/README.md
+++ b/13_factorial/README.md
@@ -1,6 +1,6 @@
 # Exercise 13 - Factorial
 
-Write a recursive function that takes a non-negative integer, and returns the product of all positive integers less than or equal to the input integer. An input of `0` should return `1`. The function should only accept numbers, so `'4'` should not be accepted as it is a string. All invalid inputs should return `undefined`.
+Write a [recursive factorial function](https://simple.wikipedia.org/wiki/Factorial) that takes a non-negative integer, and returns the product of all positive integers less than or equal to the input integer. An input of `0` should return `1`. The function should only accept numbers, so `'4'` should not be accepted as it is a string. All invalid inputs should return `undefined`.
 
 For example:
 

From 54dd2ce3f9cc7337a671a65cfc57b1fa7326d283 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sat, 23 Mar 2024 19:13:16 +0000
Subject: [PATCH 16/18] Update 13_factorial/README.md

Co-authored-by: MaoShizhong <122839503+MaoShizhong@users.noreply.github.com>
---
 13_factorial/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/13_factorial/README.md b/13_factorial/README.md
index 17831cbd7b3..ecd8388fa6a 100644
--- a/13_factorial/README.md
+++ b/13_factorial/README.md
@@ -1,6 +1,6 @@
 # Exercise 13 - Factorial
 
-Write a [recursive factorial function](https://simple.wikipedia.org/wiki/Factorial) that takes a non-negative integer, and returns the product of all positive integers less than or equal to the input integer. An input of `0` should return `1`. The function should only accept numbers, so `'4'` should not be accepted as it is a string. All invalid inputs should return `undefined`.
+Write a recursive [factorial](https://simple.wikipedia.org/wiki/Factorial) function that takes a non-negative integer, and returns the product of all positive integers less than or equal to the input integer. An input of `0` should return `1`. The function should only accept numbers, so `'4'` should not be accepted as it is a string. All invalid inputs should return `undefined`.
 
 For example:
 

From 8b2ed42f9a8547dbea98420d5892dbac02ef0231 Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Sun, 24 Mar 2024 11:20:14 +0000
Subject: [PATCH 17/18] Update 13_factorial/factorial.spec.js

Co-authored-by: MaoShizhong <122839503+MaoShizhong@users.noreply.github.com>
---
 13_factorial/factorial.spec.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/13_factorial/factorial.spec.js b/13_factorial/factorial.spec.js
index a079053b572..4250d5d9500 100644
--- a/13_factorial/factorial.spec.js
+++ b/13_factorial/factorial.spec.js
@@ -1,4 +1,4 @@
-const factorial = require("./factorial-solution");
+const factorial = require("./factorial");
 
 describe('factorial', () => {
   test('4th factorial number is 24', () => {

From 10d559dc5dfad55399fedd36050bc68053ee923d Mon Sep 17 00:00:00 2001
From: Nikita Revenco <154856872+nikitarevenco@users.noreply.github.com>
Date: Tue, 20 Aug 2024 23:28:08 +0100
Subject: [PATCH 18/18] feat(factorial): remove .skip from all tests under
 solution

---
 .../solution/factorial-solution.spec.js       | 20 +++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/13_factorial/solution/factorial-solution.spec.js b/13_factorial/solution/factorial-solution.spec.js
index 35c18e8b49c..7532f54c990 100644
--- a/13_factorial/solution/factorial-solution.spec.js
+++ b/13_factorial/solution/factorial-solution.spec.js
@@ -4,34 +4,34 @@ describe('factorial', () => {
   test('4th factorial number is 24', () => {
     expect(factorial(4)).toBe(24);
   });
-  test.skip('6th factorial number is 720', () => {
+  test('6th factorial number is 720', () => {
     expect(factorial(6)).toBe(720);
   });
-  test.skip('10th factorial number is 3628800', () => {
+  test('10th factorial number is 3628800', () => {
     expect(factorial(10)).toBe(3628800);
   });
-  test.skip('15th factorial number is 1307674368000', () => {
+  test('15th factorial number is 1307674368000', () => {
     expect(factorial(15)).toBe(1307674368000);
   });
-  test.skip('25th factorial number is 1.5511210043330986e+25', () => {
+  test('25th factorial number is 1.5511210043330986e+25', () => {
     expect(factorial(25)).toBe(1.5511210043330986e+25);
   });
-  test.skip('0th factorial number is 1', () => {
+  test('0th factorial number is 1', () => {
     expect(factorial(0)).toBe(1);
   });
-  test.skip('doesn\'t accept negatives', () => {
+  test('doesn\'t accept negatives', () => {
     expect(factorial(-25)).toBe(undefined);
   });
-  test.skip('doesn\'t accept floats', () => {
+  test('doesn\'t accept floats', () => {
     expect(factorial(5.4)).toBe(undefined);
   });
-  test.skip('doesn\'t accept a number as a string', () => {
+  test('doesn\'t accept a number as a string', () => {
     expect(factorial('5')).toBe(undefined);
   });
-  test.skip('doesn\'t accept strings', () => {
+  test('doesn\'t accept strings', () => {
     expect(factorial('foo')).toBe(undefined);
   });
-  test.skip('doesn\'t accept arrays', () => {
+  test('doesn\'t accept arrays', () => {
     expect(factorial([5])).toBe(undefined);
   });
 });