feat(cardCollection): add helpers to reduce repeated code

src/models/cardCollection/cardCollection.interface.ts

@@ -2,10 +2,12 @@ import { ICard } from '../card/card.interface'
 
 export interface ICardCollection {
   getCards (): ICard[]
+  addCard (card: ICard): ICardCollection
   addCards (cards: ICard[]): ICardCollection
   removeCards (cards: ICard[]): ICardCollection
   takeCard (): ICard
   takeCards (amount: number): ICard[]
   getCount (): number
+  hasCards (): boolean
   shuffle (): void
 }

src/models/cardCollection/cardCollection.model.ts

@@ -24,6 +24,10 @@ export class CardCollection implements ICardCollection {
 
   }
 
+  public addCard (card: ICard): this {
+    return this.addCards([card])
+  }
+
   public addCards (cards: ICard[]): this {
     this.getCards().unshift(...cards)
     return this
@@ -42,7 +46,7 @@ export class CardCollection implements ICardCollection {
   }
 
   public takeCard (): ICard {
-    if (this.getCount() > 0) {
+    if (this.hasCards()) {
       return this.getCards().shift() as ICard
     }
     throw new Error('No cards remaining in pile.')
@@ -58,7 +62,7 @@ export class CardCollection implements ICardCollection {
     }
     // tslint:disable-next-line:prefer-const
     let pulledCards: ICard[] = []
-    while (this.getCount() > 0 && pulledCards.length < amount) {
+    while (this.hasCards() && pulledCards.length < amount) {
       pulledCards.push(this.getCards().shift() as ICard)
     }
     return pulledCards
@@ -77,6 +81,10 @@ export class CardCollection implements ICardCollection {
     return this.getCards().length
   }
 
+  public hasCards (): boolean {
+    return this.getCount() > 0
+  }
+
   public shuffle (): void {
     this.setCards(this.shuffleService.shuffle(this.getCards()))
   }

src/models/cardCollection/cardPile.model.ts

@@ -20,15 +20,15 @@ export class CardPile extends CardCollection implements ICardPile {
   }
 
   public takeCardFromBottom (): ICard {
-    if (this.getCount() > 0) {
+    if (this.hasCards()) {
       return this.getCards().pop() as ICard
     }
     throw new Error('No cards remaining in pile.')
   }
 
   public takeCardsFromBottom (amount: number): ICard[] {
     let pulledCards: ICard[] = []
-    while (this.getCount() > 0 && pulledCards.length < amount) {
+    while (this.hasCards() && pulledCards.length < amount) {
       pulledCards.push(this.getCards().pop() as ICard)
     }
     return pulledCards

src/models/cardCollection/hand.model.ts

@@ -34,7 +34,7 @@ export class Hand extends CardCollection implements IHand {
    */
   public sortCards (cardRank: IRankSet): this {
     const cards = this.getCards()
-    if (cards.length === 0) {
+    if (!this.hasCards()) {
       throw new Error('No cards to sort.')
     }
     if (this.suitOrder.length === 0) {