blog_if-switch-hash.js

/* ********************    If Else/Switch Way   ********************* */
const shape = 'circle';

const getArea1 = () => {
    if (shape === 'circle') {
        getCircleArea();
    } else if (shape === 'triangle') {
        getTriangleArea();
    } else if (shape === 'rectangle') {
        getRectangleArea();
    } else if (shape === 'square') {
        getSquareArea();
    } else if (shape === 'pentagon') {
        getPentagonArea();
    } else if (shape === 'hexagon') {
        getHexagonArea();
    } else {
        unIdentifiedShape();
    }
}

// Another way to write the above piece, which is a bit better but still not great.
const getArea2 = () => {
    switch (shape) {
        case 'circle':
            getCircleArea();
            break;
        case 'triangle':
            getTriangleArea();
            break;
        case 'rectangle':
            getRectangleArea();
            break;
        case 'square':
            getSquareArea();
            break;
        case 'pentagon':
            getPentagonArea();
            break;
        case 'hexagon':
            getHexagonArea();
            break;
        default:
            unIdentifiedShape()
    }
}

/* ********************    Hashmap Way    ******************** */
const shape = 'Circle';
const SHAPE_AREAS = {
    circle: getCircleArea(),
    triangle: getTriangleArea(),
    rectangle: getRectangleArea(),
    square: getSquareArea(),
    pentagon: getPentagonArea(),
    hexagon: getHexagonArea()
};

const getArea2 = () => {
    SHAPE_AREAS[shape] || unIdentifiedShape();
}