Merge pull request #99 from riccardofano/common-denominator

Add query param to convert fractions to common denominator

core/commonDenominator.ts

@@ -0,0 +1,49 @@
+import Fraction from 'fraction.js'
+
+function gcd(a: number, b: number): number {
+  a = Math.abs(a)
+  b = Math.abs(b)
+
+  if (b > a) {
+    const temp = a
+    a = b
+    b = temp
+  }
+
+  while (true) {
+    a %= b
+    if (a === 0) {
+      return b
+    }
+    b %= a
+    if (b === 0) {
+      return a
+    }
+  }
+}
+
+function lcm(a: number, b: number): number {
+  return Math.abs(a * b) / gcd(a, b)
+}
+
+export function toCommonDenominator(list: Record<string, string>) {
+  if (Object.entries(list).length < 2) {
+    return
+  }
+
+  let denominator = 1
+  for (const str of Object.values(list)) {
+    const current = new Fraction(str)
+    denominator = lcm(denominator, current.d)
+  }
+
+  for (const [key, value] of Object.entries(list)) {
+    const current = new Fraction(value)
+    const difference = denominator / current.d
+
+    current.n *= difference
+    current.d = denominator
+
+    list[key] = current.toFraction(false)
+  }
+}

core/tests/commonDenominator.test.ts

@@ -0,0 +1,115 @@
+import { toCommonDenominator } from '../commonDenominator'
+
+test('Should handle 1 number in the list', () => {
+  const list = {
+    '0': '1/3',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('1/3')
+})
+
+test('Should handle 2 numbers in the list', () => {
+  const list = {
+    '0': '1/3',
+    '1': '1/2',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('2/6')
+  expect(list['1']).toBe('3/6')
+})
+
+test('Should handle 3 numbers in the list', () => {
+  const list = {
+    '0': '1/3',
+    '1': '1/2',
+    '2': '1/6',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('2/6')
+  expect(list['1']).toBe('3/6')
+  expect(list['2']).toBe('1/6')
+})
+
+test('Should handle a lot of numbers in the list', () => {
+  const list = {
+    '0': '1/3',
+    '1': '1/2',
+    '2': '1/6',
+    '3': '1/17',
+    '4': '1/5',
+    '5': '1/10',
+    '6': '1/70',
+    '7': '1/32',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('19040/57120')
+  expect(list['1']).toBe('28560/57120')
+  expect(list['2']).toBe('9520/57120')
+  expect(list['3']).toBe('3360/57120')
+  expect(list['4']).toBe('11424/57120')
+  expect(list['5']).toBe('5712/57120')
+  expect(list['6']).toBe('816/57120')
+  expect(list['7']).toBe('1785/57120')
+})
+
+test('Should handle 1 correctly', () => {
+  const list = {
+    '0': '1',
+    '1': '1/2',
+    '2': '1/6',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('6/6')
+  expect(list['1']).toBe('3/6')
+  expect(list['2']).toBe('1/6')
+})
+
+test('Should be able to return whole numbers', () => {
+  const list = {
+    '0': '1',
+    '1': '1',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('1')
+  expect(list['1']).toBe('1')
+})
+
+test('Should handle 0 correctly', () => {
+  const list = {
+    '0': '0',
+    '1': '1/2',
+    '2': '1/6',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('0/6')
+  expect(list['1']).toBe('3/6')
+  expect(list['2']).toBe('1/6')
+})
+
+test('Should be able to handle big numbers', () => {
+  const list = {
+    '0': '1/9',
+    '1': '1/54',
+    '2': '1/47',
+  }
+
+  toCommonDenominator(list)
+
+  expect(list['0']).toBe('282/2538')
+  expect(list['1']).toBe('47/2538')
+  expect(list['2']).toBe('54/2538')
+})

pages/api/inheritance.ts

@@ -1,10 +1,13 @@
 import { NextApiRequest, NextApiResponse } from 'next'
+
 import { calculateInheritance } from '../../core/inheritance'
+import { toCommonDenominator } from '../../core/commonDenominator'
 
 export default function handler(req: NextApiRequest, res: NextApiResponse) {
   if (req.method !== 'POST') {
     return res.status(405).send({ error: 'Method not allowed' })
   }
+
   if (req.headers['content-type'] !== 'application/json') {
     return res.status(400).send({ error: 'Content type not allowed' })
   }
@@ -13,6 +16,11 @@ export default function handler(req: NextApiRequest, res: NextApiResponse) {
 
   try {
     const result = calculateInheritance(req.body)
+
+    if (req.query['denominatorecomune'] === 'true') {
+      toCommonDenominator(result)
+    }
+
     return res.json(result)
   } catch (error) {
     return res.status(500).send({ error: 'Failed to parse body' })

pages/api/inverted/inheritance.ts

@@ -1,6 +1,8 @@
 import { NextApiRequest, NextApiResponse } from 'next'
+
 import { calculateInheritance } from '../../../core/inheritance'
 import { defaultRoot, invertGraph } from '../../../core/invertGraph'
+import { toCommonDenominator } from '../../../core/commonDenominator'
 
 export default function handler(req: NextApiRequest, res: NextApiResponse) {
   if (req.method !== 'POST') {
@@ -14,6 +16,11 @@ export default function handler(req: NextApiRequest, res: NextApiResponse) {
   try {
     const graph = invertGraph(defaultRoot(), req.body)
     const result = calculateInheritance(graph)
+
+    if (req.query['denominatorecomune'] === 'true') {
+      toCommonDenominator(result)
+    }
+
     return res.json(result)
   } catch (error) {
     return res.status(500).send({ error: 'Failed to parse body' })

pages/api/patrimony.ts

@@ -1,13 +1,24 @@
 import { NextApiRequest, NextApiResponse } from 'next'
+
 import { calculatePatrimony } from '../../core/patrimony'
+import { toCommonDenominator } from '../../core/commonDenominator'
 
 export default function handler(req: NextApiRequest, res: NextApiResponse) {
-  if (req.method !== 'POST') return res.status(405).send({ error: 'Method not allowed' })
-  if (req.headers['content-type'] !== 'application/json')
+  if (req.method !== 'POST') {
+    return res.status(405).send({ error: 'Method not allowed' })
+  }
+
+  if (req.headers['content-type'] !== 'application/json') {
     return res.status(400).send({ error: 'Content type not allowed' })
+  }
 
   try {
     const result = calculatePatrimony(req.body)
+
+    if (req.query['denominatorecomune'] === 'true') {
+      toCommonDenominator(result)
+    }
+
     return res.json(result)
   } catch (error) {
     return res.status(500).send({ error: 'Failed to parse body' })