[js][student_grades][extract_subclass] Refactor to extract subclass

Author: rgomezcasas

examples/js/js-student_grades-02_extract_subclass/src/StudentGrade2019Calculator.js

@@ -0,0 +1,11 @@
+import {StudentGradeCalculator} from "./StudentGradeCalculator";
+
+export class StudentGrade2019Calculator extends StudentGradeCalculator {
+    thisYearTeachers() {
+        return [
+            ["Eduarda", false],
+            ["Abelardo", false],
+            ["Francisca", false],
+        ];
+    }
+}

examples/js/js-student_grades-02_extract_subclass/src/StudentGrade2020Calculator.js

@@ -0,0 +1,11 @@
+import {StudentGradeCalculator} from "./StudentGradeCalculator";
+
+export class StudentGrade2020Calculator extends StudentGradeCalculator {
+    thisYearTeachers() {
+        return [
+            ["Josefina", true],
+            ["Edonisio", true],
+            ["Edufasio", false],
+        ];
+    }
+}

examples/js/js-student_grades-02_extract_subclass/src/StudentGradeCalculator.js

@@ -1,38 +1,20 @@
 export class StudentGradeCalculator {
-    allYearsTeachers = {
-        2020: [
-            ["Josefina", true],
-            ["Edonisio", true],
-            ["Edufasio", false],
-        ],
-        2019: [
-            ["Eduarda", false],
-            ["Abelardo", false],
-            ["Francisca", false],
-        ]
-    };
-    
-    constructor(yearToCalculate) {
-        this.yearToCalculate = yearToCalculate;
+    thisYearTeachers() {
+        throw 'This method should be implemented';
     }
 
     calculate(examGrades, hasReachedMinimumClasses) {
         if (examGrades.length !== 0) {
             let hasToIncreaseOneExtraPoint = false;
-            
-            for (let [year, teachers] of Object.entries(this.allYearsTeachers)) {
-                if (!(this.yearToCalculate != year)) {
-                    for (let teacher of teachers) {
-                        if (teacher[1] != true) {
-                            continue;
-                        }
-                        
-                        hasToIncreaseOneExtraPoint = true;
-                    }
-                } else {
+    
+            for (let teacher of this.thisYearTeachers()) {
+                if (teacher[1] != true) {
                     continue;
                 }
+        
+                hasToIncreaseOneExtraPoint = true;
             }
+    
 
             let gradesSum       = 0;
             let gradesWeightSum = 0;

examples/js/js-student_grades-02_extract_subclass/tests/StudentGradeCalculator.test.js

@@ -1,8 +1,9 @@
-import {StudentGradeCalculator} from '../src/StudentGradeCalculator';
+import {StudentGrade2019Calculator} from "../src/StudentGrade2019Calculator";
+import {StudentGrade2020Calculator} from "../src/StudentGrade2020Calculator";
 
 describe('StudentGradeCalculator should', () => {
     it('fail given there are no exams', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [];
         const hasReachedMinimumClasses = true;
@@ -11,7 +12,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('calculate same grade given one single exam and attending the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [[100, 5]];
         const hasReachedMinimumClasses = true;
@@ -20,7 +21,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('calculate average grade given different exam grades and attending the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [
             [10, 4],
@@ -40,7 +41,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('round up to 2 decimals given odd exam grades and attending the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [
             [50, 4],
@@ -54,7 +55,7 @@ describe('StudentGradeCalculator should', () => {
     // hasReachedMinimumClasses
 
     it('fail when there are no exams and has not attended the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [];
         const hasReachedMinimumClasses = false;
@@ -63,7 +64,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('fail given one single exam but not attending the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [[100, 5]];
         const hasReachedMinimumClasses = false;
@@ -72,7 +73,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('fail given different exam grades but not attending the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [
             [10, 4],
@@ -92,7 +93,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('fail given odd exam grades but not attending the minimum classes', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [[50, 5], [50, 4]];
         const hasReachedMinimumClasses = false;
@@ -103,7 +104,7 @@ describe('StudentGradeCalculator should', () => {
     // Weight
 
     it('validate all exam grades weight below 100', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [
             [10, 4],
@@ -115,7 +116,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('validate all exam grades weight over 100', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [
             [90, 4],
@@ -129,16 +130,16 @@ describe('StudentGradeCalculator should', () => {
     // hasToRaiseOnePoint
 
     it('not increase one extra point if there is not any benevolent teacher in the year to calculate grades', () => {
-        const calculator = new StudentGradeCalculator(2019);
+        const calculator = new StudentGrade2019Calculator();
 
         const examsGrades              = [[100, 9.8]];
         const hasReachedMinimumClasses = true;
 
         expect(calculator.calculate(examsGrades, hasReachedMinimumClasses)).toBe(9.8);
     });
-   
+    
     it('increase one extra point if there is any benevolent teacher in the year to calculate grades', () => {
-        const calculator = new StudentGradeCalculator(2020);
+        const calculator = new StudentGrade2020Calculator();
 
         const examsGrades              = [[100, 5]];
         const hasReachedMinimumClasses = true;
@@ -147,7 +148,7 @@ describe('StudentGradeCalculator should', () => {
     });
 
     it('maintain 10 as the maximum grade even if increasing one extra point', () => {
-        const calculator = new StudentGradeCalculator(2020);
+        const calculator = new StudentGrade2020Calculator();
 
         const examsGrades              = [[100, 9.8]];
         const hasReachedMinimumClasses = true;