← 输入框|github.com|刷新
Skip to content

feat: add digital root algorithm #2001

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
sarthakgupta1907-cell wants to merge 1 commit into
base: master
Choose a base branch
from
+72 −0
Open

feat: add digital root algorithm #2001

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 21 additions & 0 deletions Maths/DigitalRoot.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
/**
* @function digitalRoot
* @description The digital root is the single digit obtained by repeatedly
* summing the digits of a number until a single digit is reached.
* For example, 493: 4+9+3=16, 1+6=7 — digital root is 7.
* @param {number} n - A non-negative integer
* @returns {number} - The digital root of n
* @see https://en.wikipedia.org/wiki/Digital_root
* @example digitalRoot(493) => 7
* @example digitalRoot(999) => 9
* @example digitalRoot(0) => 0
*/
const digitalRoot = (n) => {
if (!Number.isInteger(n) || n < 0) {
throw new TypeError('Input must be a non-negative integer')
}
if (n === 0) return 0
return n % 9 === 0 ? 9 : n % 9
}

export { digitalRoot }
51 changes: 51 additions & 0 deletions Maths/test/DigitalRoot.test.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,51 @@
import { digitalRoot } from '../DigitalRoot.js'

describe('digitalRoot', () => {
test('digitalRoot(0) returns 0', () => {
expect(digitalRoot(0)).toBe(0)
})

test('digitalRoot(1) returns 1', () => {
expect(digitalRoot(1)).toBe(1)
})

test('digitalRoot(9) returns 9', () => {
expect(digitalRoot(9)).toBe(9)
})

test('digitalRoot(493) returns 7', () => {
expect(digitalRoot(493)).toBe(7)
})

test('digitalRoot(999) returns 9', () => {
expect(digitalRoot(999)).toBe(9)
})

test('digitalRoot(18) returns 9', () => {
expect(digitalRoot(18)).toBe(9)
})

test('digitalRoot(99) returns 9', () => {
expect(digitalRoot(99)).toBe(9)
})

test('digitalRoot(100) returns 1', () => {
expect(digitalRoot(100)).toBe(1)
})

test('digitalRoot(12345) returns 6', () => {
expect(digitalRoot(12345)).toBe(6)
})

test('throws TypeError for negative input', () => {
expect(() => digitalRoot(-493)).toThrow(TypeError)
})

test('throws TypeError for float input', () => {
expect(() => digitalRoot(4.93)).toThrow(TypeError)
})

test('throws TypeError for string input', () => {
expect(() => digitalRoot('493')).toThrow(TypeError)
})
})
Loading