From 865cbdba53471fe05b2d2e48d0ab4c1ce6d1f021 Mon Sep 17 00:00:00 2001
From: "github@esslinger.dev" <simon@esslinger.dev>
Date: Sat, 8 Oct 2022 10:09:56 +0200
Subject: [PATCH 1/5] feat(maths): add Factorial
---
Maths/Factorial.ts | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
create mode 100644 Maths/Factorial.ts
diff --git a/Maths/Factorial.ts b/Maths/Factorial.ts
new file mode 100644
index 00000000..883878f4
--- /dev/null
+++ b/Maths/Factorial.ts
@@ -0,0 +1,20 @@
+/**
+ * @function Factorial
+ * @description Calculate the factorial of a positive integer.
+ * @param {number} num - A positive number.
+ * @return {number} - The factorial.
+ * @see https://en.wikipedia.org/wiki/Factorial
+ * @example Factorial(0) = 1
+ * @example Factorial(3) = 6
+ */
+export const Factorial = (num: number): number => {
+ if (num < 0) {
+ throw new Error("num must be >= 0");
+ }
+
+ if (!Number.isInteger(num)){
+ throw new Error("only integers are supported");
+ }
+
+ return num === 0 ? 1 : num * Factorial(num - 1);
+};
From 66611ff7b45b0c97f349050f6bb2ac722d5002a7 Mon Sep 17 00:00:00 2001
From: "github@esslinger.dev" <simon@esslinger.dev>
Date: Sat, 8 Oct 2022 10:10:11 +0200
Subject: [PATCH 2/5] test(maths): add Factorial tests
---
Maths/test/Factorial.test.ts | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
create mode 100644 Maths/test/Factorial.test.ts
diff --git a/Maths/test/Factorial.test.ts b/Maths/test/Factorial.test.ts
new file mode 100644
index 00000000..daca38b1
--- /dev/null
+++ b/Maths/test/Factorial.test.ts
@@ -0,0 +1,21 @@
+import { Factorial } from '../Factorial';
+
+describe('Factorial', () => {
+
+ test.each([-0.1, -1, -2, -42])('should throw an error for numbers < 0 like %i', (num) => {
+ expect(() => Factorial(num)).toThrowError("num must be >= 0");
+ })
+
+ test.each([0.01, 0.42, 0.5, 1.337])('should throw an error for numbers that are not integers like %i', (num) => {
+ expect(() => Factorial(num)).toThrowError("only integers are supported");
+ })
+
+ test.each([[1, 1], [3, 6], [5, 120], [10, 3628800] ])('of %i should be %i', (num, expected) => {
+ expect(Factorial(num)).toBe(expected);
+ })
+
+ test('of 1 should be 0 by definition', () => {
+ expect(Factorial(0)).toBe(1);
+ });
+
+});
From cdca414c61374ad00c4d881d2f75ce3737e6f414 Mon Sep 17 00:00:00 2001
From: "github@esslinger.dev" <simon@esslinger.dev>
Date: Sat, 8 Oct 2022 10:12:37 +0200
Subject: [PATCH 3/5] chore(math): use integer instead of number in jsdoc of
Factorial
---
Maths/Factorial.ts | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Maths/Factorial.ts b/Maths/Factorial.ts
index 883878f4..9de57d5c 100644
--- a/Maths/Factorial.ts
+++ b/Maths/Factorial.ts
@@ -1,7 +1,7 @@
/**
* @function Factorial
* @description Calculate the factorial of a positive integer.
- * @param {number} num - A positive number.
+ * @param {number} num - A positive integer.
* @return {number} - The factorial.
* @see https://en.wikipedia.org/wiki/Factorial
* @example Factorial(0) = 1
From ece0a5586dc003e3dac6ce2a82f5ea7c951936b0 Mon Sep 17 00:00:00 2001
From: "github@esslinger.dev" <simon@esslinger.dev>
Date: Sat, 8 Oct 2022 10:37:47 +0200
Subject: [PATCH 4/5] style: format code
---
Maths/Factorial.ts | 2 +-
Maths/test/Factorial.test.ts | 35 +++++++++++++++++++++--------------
2 files changed, 22 insertions(+), 15 deletions(-)
diff --git a/Maths/Factorial.ts b/Maths/Factorial.ts
index 9de57d5c..179c2716 100644
--- a/Maths/Factorial.ts
+++ b/Maths/Factorial.ts
@@ -12,7 +12,7 @@ export const Factorial = (num: number): number => {
throw new Error("num must be >= 0");
}
- if (!Number.isInteger(num)){
+ if (!Number.isInteger(num)) {
throw new Error("only integers are supported");
}
diff --git a/Maths/test/Factorial.test.ts b/Maths/test/Factorial.test.ts
index daca38b1..110f5bf8 100644
--- a/Maths/test/Factorial.test.ts
+++ b/Maths/test/Factorial.test.ts
@@ -1,21 +1,28 @@
-import { Factorial } from '../Factorial';
+import { Factorial } from "../Factorial";
-describe('Factorial', () => {
+describe("Factorial", () => {
+ test.each([-0.1, -1, -2, -42])(
+ "should throw an error for numbers < 0 like %i",
+ (num) => {
+ expect(() => Factorial(num)).toThrowError("num must be >= 0");
+ },
+ );
- test.each([-0.1, -1, -2, -42])('should throw an error for numbers < 0 like %i', (num) => {
- expect(() => Factorial(num)).toThrowError("num must be >= 0");
- })
+ test.each([0.01, 0.42, 0.5, 1.337])(
+ "should throw an error for numbers that are not integers like %i",
+ (num) => {
+ expect(() => Factorial(num)).toThrowError("only integers are supported");
+ },
+ );
- test.each([0.01, 0.42, 0.5, 1.337])('should throw an error for numbers that are not integers like %i', (num) => {
- expect(() => Factorial(num)).toThrowError("only integers are supported");
- })
+ test.each([[1, 1], [3, 6], [5, 120], [10, 3628800]])(
+ "of %i should be %i",
+ (num, expected) => {
+ expect(Factorial(num)).toBe(expected);
+ },
+ );
- test.each([[1, 1], [3, 6], [5, 120], [10, 3628800] ])('of %i should be %i', (num, expected) => {
- expect(Factorial(num)).toBe(expected);
- })
-
- test('of 1 should be 0 by definition', () => {
+ test("of 1 should be 0 by definition", () => {
expect(Factorial(0)).toBe(1);
});
-
});
From 7929fb78acca7a46d075b7695fcf74c5237fa4d3 Mon Sep 17 00:00:00 2001
From: "github@esslinger.dev" <simon@esslinger.dev>
Date: Sat, 8 Oct 2022 10:40:30 +0200
Subject: [PATCH 5/5] refactor: simplify code
---
Maths/Factorial.ts | 12 ++++--------
Maths/test/Factorial.test.ts | 15 +++++----------
2 files changed, 9 insertions(+), 18 deletions(-)
diff --git a/Maths/Factorial.ts b/Maths/Factorial.ts
index 179c2716..1783383b 100644
--- a/Maths/Factorial.ts
+++ b/Maths/Factorial.ts
@@ -1,19 +1,15 @@
/**
* @function Factorial
- * @description Calculate the factorial of a positive integer.
- * @param {number} num - A positive integer.
+ * @description Calculate the factorial of a natural number.
+ * @param {number} num - A natural number.
* @return {number} - The factorial.
* @see https://en.wikipedia.org/wiki/Factorial
* @example Factorial(0) = 1
* @example Factorial(3) = 6
*/
export const Factorial = (num: number): number => {
- if (num < 0) {
- throw new Error("num must be >= 0");
- }
-
- if (!Number.isInteger(num)) {
- throw new Error("only integers are supported");
+ if (num < 0 || !Number.isInteger(num)) {
+ throw new Error("only natural numbers are supported");
}
return num === 0 ? 1 : num * Factorial(num - 1);
diff --git a/Maths/test/Factorial.test.ts b/Maths/test/Factorial.test.ts
index 110f5bf8..5ce5ccba 100644
--- a/Maths/test/Factorial.test.ts
+++ b/Maths/test/Factorial.test.ts
@@ -1,17 +1,12 @@
import { Factorial } from "../Factorial";
describe("Factorial", () => {
- test.each([-0.1, -1, -2, -42])(
- "should throw an error for numbers < 0 like %i",
+ test.each([-0.1, -1, -2, -42, 0.01, 0.42, 0.5, 1.337])(
+ "should throw an error for non natural number %d",
(num) => {
- expect(() => Factorial(num)).toThrowError("num must be >= 0");
- },
- );
-
- test.each([0.01, 0.42, 0.5, 1.337])(
- "should throw an error for numbers that are not integers like %i",
- (num) => {
- expect(() => Factorial(num)).toThrowError("only integers are supported");
+ expect(() => Factorial(num)).toThrowError(
+ "only natural numbers are supported",
+ );
},
);