Solution Samy Navet

.babelrc

@@ -1,3 +1,3 @@
 {
-  "presets": ["@babel/preset-env"]
+  "presets": ["@babel/preset-env", "@babel/preset-typescript"]
 }

index.js → index.ts

@@ -1,4 +1,5 @@
-import { Drug, Pharmacy } from "./pharmacy";
+import { Pharmacy } from "./src/pharmacy/pharmacy";
+import { Drug } from "./src/drug/drug";
 import fs from "fs";
 
 const drugs = [

package.json

@@ -12,7 +12,7 @@
   "scripts": {
     "lint": "eslint .",
     "test": "jest",
-    "start": "babel-node index.js"
+    "start": "babel-node --extensions \".ts\" index.ts"
   },
   "devDependencies": {
     "@babel/cli": "^7.1.0",
@@ -28,5 +28,8 @@
     "jest": "24.8.0",
     "prettier": "^1.14.3",
     "regenerator-runtime": "^0.12.1"
+  },
+  "dependencies": {
+    "@babel/preset-typescript": "^7.16.7"
   }
 }

src/drug/drug.test.js

@@ -0,0 +1,31 @@
+import { benefitEvolutionRules, HERBAL_TEA } from "./drug";
+
+describe("Pharmacy", () => {
+  it("should decrease the benefit according default rule", () => {
+    expect(benefitEvolutionRules.default(3, 1)).toEqual(2);
+    expect(benefitEvolutionRules.default(3, -1)).toEqual(1);
+
+    /* i could check in my function if the parameters are NaN, 
+    Infinite or other type but it is not the interessting part of the exercise */
+
+    expect(benefitEvolutionRules.default(NaN, 1)).toEqual(NaN);
+    expect(benefitEvolutionRules.default(1, NaN)).toEqual(-1);
+    expect(benefitEvolutionRules.default(Infinity, 1)).toEqual(Infinity);
+    expect(benefitEvolutionRules.default("tototo", 1)).toEqual(NaN);
+  });
+  it("should check update fervex benefit according its rules", () => {
+    expect(benefitEvolutionRules.Fervex(20, 11)).toBe(21);
+    expect(benefitEvolutionRules.Fervex(20, 9)).toBe(22);
+    expect(benefitEvolutionRules.Fervex(20, 4)).toBe(23);
+    expect(benefitEvolutionRules.Fervex(20, 0)).toBe(0);
+  });
+  it("should check update Herbal Tea benefit according its rules", () => {
+    expect(benefitEvolutionRules[HERBAL_TEA](20, 1)).toBe(21);
+    expect(benefitEvolutionRules[HERBAL_TEA](20, 0)).toBe(22);
+  });
+  it("should check update dafalgan benefit according its rules", () => {
+    expect(benefitEvolutionRules.Dafalgan(10, 1)).toBe(8);
+    expect(benefitEvolutionRules.Dafalgan(10, 0)).toBe(6);
+    expect(benefitEvolutionRules.Dafalgan(10, -1)).toBe(6);
+  });
+});

src/drug/drug.ts

@@ -0,0 +1,71 @@
+export interface DrugInterface {
+  name: string;
+  expiresIn: number;
+  benefit: number;
+  checkBenefit: () => void;
+  canUpdateBenefit: () => boolean;
+}
+
+export class Drug implements DrugInterface {
+  name: string;
+  expiresIn: number;
+  benefit: number;
+  constructor(name, expiresIn, benefit) {
+    this.name = name;
+    this.expiresIn = expiresIn;
+    this.benefit = benefit;
+  }
+
+  checkBenefit() {
+    if (this.benefit > 50) this.benefit = 50;
+    if (this.benefit < 0) this.benefit = 0;
+  }
+
+  /* cela marche dans le cadre de l'exercice, 
+  cependant ce n'est pas la meilleur façon de faire si de nouveaux cas particuliers arrivent */
+  canUpdateBenefit() {
+    return (
+      (this.benefit < 50 && this.benefit > 0) ||
+      (this.name === FERVEX && this.benefit !== 0)
+    );
+  }
+}
+
+export const DEFAULT = "default";
+export const MAGIC_PILL = "Magic Pill";
+export const HERBAL_TEA = "Herbal Tea";
+const FERVEX = "Fervex";
+const DAFALGAN = "Dafalgan";
+
+const BENEFIT_CHANGE = 1;
+
+type updateBenefitFunction = (benefit: number, expiresIn?: number) => number;
+
+const getDefaultBenefitUpdate = (expiresIn: number): number =>
+  expiresIn > 0 ? BENEFIT_CHANGE : BENEFIT_CHANGE * 2;
+
+const updateDefautDrugBenefit: updateBenefitFunction = (benefit, expiresIn) =>
+  benefit - getDefaultBenefitUpdate(expiresIn);
+
+const updateUpgradingDrugsBenefit: updateBenefitFunction = (
+  benefit,
+  expiresIn
+): number => benefit + getDefaultBenefitUpdate(expiresIn);
+
+const upgradeDafalganBenefit: updateBenefitFunction = (benefit, expiresIn) =>
+  benefit - 2 * getDefaultBenefitUpdate(expiresIn);
+
+const updateFervexBenefit: updateBenefitFunction = (benefit, expiresIn) => {
+  if (expiresIn <= 0) return 0;
+  if (expiresIn <= 5) return benefit + BENEFIT_CHANGE * 3;
+  if (expiresIn <= 10) return benefit + BENEFIT_CHANGE * 2;
+  return benefit + BENEFIT_CHANGE;
+};
+
+export const benefitEvolutionRules: { [key: string]: updateBenefitFunction } = {
+  [DEFAULT]: updateDefautDrugBenefit,
+  [HERBAL_TEA]: updateUpgradingDrugsBenefit,
+  [FERVEX]: updateFervexBenefit,
+  [MAGIC_PILL]: benefit => benefit,
+  [DAFALGAN]: upgradeDafalganBenefit
+};

pharmacy.test.js → src/pharmacy/pharmacy.test.js

@@ -1,4 +1,5 @@
-import { Drug, Pharmacy } from "./pharmacy";
+import { Pharmacy } from "./pharmacy";
+import { Drug } from "../drug/drug";
 
 describe("Pharmacy", () => {
   it("should decrease the benefit and expiresIn", () => {

src/pharmacy/pharmacy.ts

@@ -0,0 +1,31 @@
+import { benefitEvolutionRules, DEFAULT, Drug, MAGIC_PILL } from "../drug/drug";
+
+interface PharmacyInterface {
+  drugs: Drug[];
+  updateBenefitValue: () => Drug[];
+}
+
+export class Pharmacy implements PharmacyInterface {
+  drugs: Drug[];
+  constructor(drugs = []) {
+    this.drugs = drugs;
+  }
+  updateBenefitValue() {
+    for (var i = 0; i < this.drugs.length; i++) {
+      const { expiresIn, benefit, name } = this.drugs[i];
+
+      if (name != MAGIC_PILL) {
+        this.drugs[i].expiresIn = expiresIn - 1;
+      }
+
+      if (this.drugs[i].canUpdateBenefit()) {
+        const benefitRule =
+          benefitEvolutionRules[name] || benefitEvolutionRules[DEFAULT];
+        this.drugs[i].benefit = benefitRule(benefit, expiresIn);
+        this.drugs[i].checkBenefit();
+      }
+    }
+
+    return this.drugs;
+  }
+}