|
| 1 | +// Wrong way |
| 2 | +class ShapeCalculator { |
| 3 | + calculateArea(shape) { |
| 4 | + if (shape.type === 'circle'){ |
| 5 | + return Math.PI * Math.pow(shape.radius, 2); |
| 6 | + } else if (shape.type === 'square') { |
| 7 | + return Math.pow(shape.side, 2); |
| 8 | + } else { |
| 9 | + throw new Error('Shape not supported'); |
| 10 | + } |
| 11 | + } |
| 12 | +} |
| 13 | + |
| 14 | +const calculator = new ShapeCalculator(); |
| 15 | +console.log(calculator.calculateArea({ type: 'circle', radius: 5 })); |
| 16 | +console.log(calculator.calculateArea({ type: 'square', side: 4 })); |
| 17 | + |
| 18 | +// Correct way |
| 19 | +class Shape { |
| 20 | + calculateArea(shape) { |
| 21 | + throw new Error('calculateArea() must be implemented'); |
| 22 | + } |
| 23 | +} |
| 24 | + |
| 25 | +class Circle extends Shape { |
| 26 | + constructor(radius) { |
| 27 | + super(); |
| 28 | + this.radius = radius; |
| 29 | + } |
| 30 | + |
| 31 | + calculateArea() { |
| 32 | + return Math.PI * Math.pow(this.radius, 2); |
| 33 | + } |
| 34 | +} |
| 35 | + |
| 36 | +class Square extends Shape { |
| 37 | + constructor(side) { |
| 38 | + super(); |
| 39 | + this.side = side; |
| 40 | + } |
| 41 | + |
| 42 | + calculateArea() { |
| 43 | + return Math.pow(this.side, 2); |
| 44 | + } |
| 45 | +} |
| 46 | + |
| 47 | +function printArea(shape) { |
| 48 | + console.log(`Area: ${shape.calculateArea()}`); |
| 49 | +} |
| 50 | + |
| 51 | +const circle = new Circle(5); |
| 52 | +const square = new Square(4); |
| 53 | +printArea(circle); |
| 54 | +printArea(square); |
| 55 | + |
| 56 | +// Extra Exercise // |
| 57 | +class Operation { |
| 58 | + calculate(a, b) { |
| 59 | + throw new Error('calculateOperation() must be implemented'); |
| 60 | + } |
| 61 | +} |
| 62 | + |
| 63 | +class Addition extends Operation { |
| 64 | + calculate(a, b) { |
| 65 | + return a + b; |
| 66 | + } |
| 67 | +} |
| 68 | + |
| 69 | +class Subtraction extends Operation { |
| 70 | + calculate(a, b) { |
| 71 | + return a - b; |
| 72 | + } |
| 73 | +} |
| 74 | + |
| 75 | +class Multiplication extends Operation { |
| 76 | + calculate(a, b) { |
| 77 | + return a * b; |
| 78 | + } |
| 79 | +} |
| 80 | + |
| 81 | +class Division extends Operation { |
| 82 | + calculate(a, b) { |
| 83 | + if (b === 0) throw new Error('Division by zero is not allowed'); |
| 84 | + return a / b; |
| 85 | + } |
| 86 | +} |
| 87 | + |
| 88 | +class Pow extends Operation { |
| 89 | + calculate(a, b) { |
| 90 | + return Math.pow(a, b); |
| 91 | + } |
| 92 | +} |
| 93 | + |
| 94 | +class Calculator { |
| 95 | + constructor() { |
| 96 | + this.operations = {}; |
| 97 | + } |
| 98 | + |
| 99 | + addOperation(name, operation) { |
| 100 | + this.operations[name] = operation; |
| 101 | + } |
| 102 | + |
| 103 | + calculate(name, a, b) { |
| 104 | + const operation = this.operations[name]; |
| 105 | + if (!operation) throw new Error(`Operation "${name}" not supported`); |
| 106 | + return operation.calculate(a, b); |
| 107 | + } |
| 108 | +} |
| 109 | + |
| 110 | +const calculator2 = new Calculator(); |
| 111 | +calculator2.addOperation('addition', new Addition()); |
| 112 | +calculator2.addOperation('subtraction', new Subtraction()); |
| 113 | +calculator2.addOperation('multiplication', new Multiplication()); |
| 114 | +calculator2.addOperation('division', new Division()); |
| 115 | +calculator2.addOperation('pow', new Pow()); |
| 116 | + |
| 117 | +console.log(calculator2.calculate('addition', 2, 10)); |
| 118 | +console.log(calculator2.calculate('subtraction', 2, 10)); |
| 119 | +console.log(calculator2.calculate('multiplication', 2, 10)); |
| 120 | +console.log(calculator2.calculate('division', 10, 5)); |
| 121 | +console.log(calculator2.calculate('pow', 10, 2)); |
| 122 | + |
| 123 | + |
0 commit comments