[ABF-7927] dev(capital gains inclusion): ajout d'une fonction pour ca…

…lculer le montant d'inclusion pour les gains en capital (#447)

* added function to calculate amount that will be taxed for capital gains

added babel dependencies to support debugging jest tests from intellij

* fix var declaration

* exporting file

* floor version for babel

* cleanup function

babel.config.js

@@ -0,0 +1 @@
+module.exports = {presets: ['@babel/preset-env', '@babel/preset-typescript']}

package.json

@@ -34,14 +34,20 @@
     "watch": "tsc --watch"
   },
   "devDependencies": {
+    "@babel/core": "7.24.5",
+    "@babel/preset-env": "7.24.5",
+    "@babel/preset-typescript": "7.24.1",
     "@equisoft/eslint-config": "3.0.6",
     "@equisoft/eslint-config-typescript": "3.0.6",
     "@equisoft/typescript-config": "2.0.0",
     "@microsoft/eslint-formatter-sarif": "3.1.0",
+    "@types/babel__core": "^7",
+    "@types/babel__preset-env": "^7",
     "@types/jest": "29.5.12",
     "@types/node": "20.12.9",
     "@typescript-eslint/eslint-plugin": "6.21.0",
     "@typescript-eslint/parser": "6.21.0",
+    "babel-jest": "29.7.0",
     "eslint": "8.57.0",
     "eslint-import-resolver-node": "0.3.9",
     "eslint-import-resolver-typescript": "3.6.1",

src/investments/index.ts

@@ -2,3 +2,4 @@ export * from './life-income-fund';
 export * from './registered-retirement-income-fund';
 export * from './registered-retirement-savings-plan';
 export * from './tax-free-savings-account';
+export * from './non-registered-savings-plan';

src/investments/non-registered-savings-plan.ts

@@ -0,0 +1,26 @@
+import { Rate } from '../taxes';
+
+export const CAPITAL_GAINS_BRACKETS: Rate[] = [
+    {
+        FROM: 0,
+        TO: 250000,
+        RATE: 0.5,
+    },
+    {
+        FROM: 250000,
+        TO: Infinity,
+        RATE: 0.667,
+    },
+];
+
+export function getCapitalGainsTaxableAmount(totalCapitalGains: number): number {
+    return CAPITAL_GAINS_BRACKETS.reduce((taxableAmount, currentBracket) => {
+        const currentBracketRate = currentBracket.RATE;
+
+        const bracketTaxableAmount = Math.min(totalCapitalGains, currentBracket.TO);
+
+        if (bracketTaxableAmount <= currentBracket.FROM) return taxableAmount;
+
+        return taxableAmount + ((bracketTaxableAmount - currentBracket.FROM) * currentBracketRate);
+    }, 0);
+}

src/investments/tests/non-registered-retirement-savings-plan.spec.ts

@@ -0,0 +1,22 @@
+import { getCapitalGainsTaxableAmount } from '../non-registered-savings-plan';
+
+describe('getCapitalGainsTaxableAmount', () => {
+    it('should calculate taxable amount on capital gains income', () => {
+        const capitalGainsList = [
+            { capitalGains: 150000, taxableAmount: 75000 },
+            { capitalGains: 0, taxableAmount: 0 },
+            { capitalGains: -50, taxableAmount: 0 },
+            { capitalGains: 250000, taxableAmount: 125000 },
+            { capitalGains: 350000, taxableAmount: 125000 + 66700 },
+            { capitalGains: 350001, taxableAmount: 125000 + 66700.667 },
+            { capitalGains: 250100, taxableAmount: 125000 + 66.7 },
+            { capitalGains: 249000, taxableAmount: 124500 },
+            { capitalGains: 250001, taxableAmount: 125000 + 0.667 },
+        ];
+
+        capitalGainsList.forEach((item) => {
+            const taxableAmount = getCapitalGainsTaxableAmount(item.capitalGains);
+            expect(taxableAmount).toBe(item.taxableAmount);
+        });
+    });
+});

tests/jest.config.js

@@ -10,6 +10,7 @@ module.exports = {
                 tsconfig: path.resolve(__dirname, 'tsconfig.json'),
             },
         ],
+        '^.+\\.(js|jsx)$': 'babel-jest',
     },
     clearMocks: true,
     errorOnDeprecated: true,