feat: replace math.js with self developed algorithm #18

	name: CI
	on:
	push:
	branches: [ "master"]
	paths-ignore:
	- "README.md"
	pull_request:
	branches: [ "master" ]

	jobs:
	test:
	services:
	mongo:
	image: mongo:6.0.20
	ports:
	- 27017:27017
	# health check
	# ref: https://engineering.synatic.com/a-simple-way-to-run-a-mongodb-replica-set-in-github-actions
	options: >-
	--health-cmd "mongosh --eval 'db.runCommand(\"ping\")'"
	--health-interval 10s
	--health-timeout 5s
	--health-retries 5
	env:
	MONGODB_URI: mongodb://localhost:27017
	strategy:
	matrix:
	directory: [ "./backend" ]
	name: 🎉 Test
	runs-on: ubuntu-latest
	steps:
	- name: 🚚 Get latest code
	uses: actions/checkout@v4
	- name: Setup node
	uses: actions/setup-node@v4
	with:
	node-version-file: ${{ matrix.directory }}/.nvmrc
	- name: 📦 Install dependencies
	working-directory: ${{ matrix.directory }}
	run: npm ci
	- name: Linter
	working-directory: ${{ matrix.directory }}
	run: npm run lint
	- name: Test
	working-directory: ${{ matrix.directory }}
	run: npm test

Provide feedback