trikitrok

// After changing the code, Invoice should look like:

export class Invoice {
    private readonly shippingPricer: ShippingPricer;
    // ...

    constructor(
        billingDate: OurDate,
        openingDate: OurDate,
        originator: Originator,

trikitrok

export class Invoice {
    //...

    public getValue(): Money {
        const total = this.itemsSum();
        if (this.billingDate.after(OurDate.yearEnd(this.openingDate))) {
            if (
                this.originator.getState() === "FL" ||
                this.originator.getState() === "NY"
            ) {

trikitrok

export class Element {
    private readonly name: string;
    private text: string;

    constructor(name: string) {
        this.name = name;
        this.text = "";
    }

    addText(newText: string): void {

trikitrok

export class InMemoryDirectory {
    private readonly elements: Element[];

    constructor() {
        this.elements = [];
    }

    public addElement(newElement: Element): void {
        this.elements.push(newElement);
    }

trikitrok

export class CppClass {
    private readonly name: string;
    private readonly declarations: Declaration[];

    constructor(name: string, declarations: Declaration[]) {
        this.name = name;
        this.declarations = declarations;
    }

    public getDeclarationCount(): number {

trikitrok

export class Reservation {
    private duration: number;
    private dailyRate: number;
    private readonly date: Date;
    private readonly customer: Customer;
    private readonly fees: FeeRider[];

    constructor(customer: Customer, duration: number, dailyRate: number, date: Date) {
        this.fees = [];
        this.customer = customer;

trikitrok

// an abstract Rule class that each of our business rules will extend.

export abstract class Rule {
    private readonly nextRule: Rule | null;

    protected constructor(nextRule: Rule | null = null) {
        this.nextRule = nextRule;
    }

    // Does this rule apply to the given player and page?

trikitrok

export class BannerAdChooser {
    private readonly bannerDao = new BannerDao();
    private readonly bannerCache = new BannerCache();

    public getAd(player: Player, page: Page): Banner {
        let banner: Banner;
        let showBanner = true;

        // First try the cache
        banner = this.bannerCache.get(player, page);

trikitrok

// Step 4
export class GDIBrush implements PointRenderer  {
    colorId: number;

    public draw(renderingRoots: Point[], colors: ColorMatrix, selection: Point[]): void {
        const renderer = new Renderer(this, renderingRoots, colors, selection);
        renderer.draw(); // !!! -> we call the method object
    }

    drawPoint(x: number, y: number, color: Color): void {

trikitrok

// Step 3

 // !!! ->  extracted interface with the things the
 // object method uses from the original class
export interface PointRenderer {
    readonly colorId: number;
    drawPoint(x: number, y: number, color: Color): void;
}

// !!! -> the original class implements it