Add method for writing/reading Deck to/from string (#33)

src/__tests__/deck.test.ts

@@ -1,5 +1,6 @@
 import { Card, Deck } from '../two-to-seven-triple-draw';
 import { isSorted } from '../arr';
+import { Cards } from '../card';
 
 describe('Deck', (): void => {
   const asCardsArray = (deck: Deck): Card[] => {
@@ -44,4 +45,16 @@ describe('Deck', (): void => {
     expect(deck.popN(52)).toHaveLength(52);
     expect(deck.cardsRemaining).toEqual(52 * 2);
   });
+  it('provides method to read deck from string', (): void => {
+    const deck = Deck.fromString('_XYZabc');
+
+    expect(deck.cardsRemaining).toEqual(6);
+    const cards = deck.popN(6).reverse();
+    expect(cards).toEqual(new Cards([23, 24, 25, 26, 27, 28]));
+  });
+  it('provides method to write the deck into a string', (): void => {
+    const deck = Deck.fromString('Ah As Ad Ac');
+
+    expect(deck.toString()).toEqual('_ANan');
+  });
 });

src/card.ts

@@ -10,6 +10,7 @@ export enum CardSuits {
 }
 
 export enum CardStringType {
+  Char = 'CHAR',
   Short = 'SHORT',
   Long = 'LONG',
   ShortEmoji = 'SHORT_EMOJI',
@@ -54,18 +55,34 @@ const stringToNum = (cardStr: string): number => {
   return suitMap[suitKey] * 13 + rank;
 };
 
+const parseString = (input: string) => {
+  const charStrRe = /^_[a-z]+$/i;
+  if (input.match(charStrRe)) {
+    const chars = Array.from(input.slice(1));
+    return chars.map((i) => {
+      const c = i.charCodeAt(0);
+      // A = 65, a = 97
+      return c < 91 ? c - 65 : c - 97 + 26;
+    });
+  }
+  return input.split(/[\s,]+/);
+};
+
 export class Cards extends Array<Card> {
   constructor(input: string | number | string[] | number[] | Card[]) {
     if (typeof input === 'number') {
       super(input);
     } else {
       super();
-      const arr = Array.isArray(input) ? input : input.split(/[\s,]+/);
+      const arr = Array.isArray(input) ? input : parseString(input);
       arr.forEach((i) => this.push(new Card(i)));
     }
   }
 
-  public toString(stringType = Card.StringType.Long): string {
+  public toString(stringType = Card.StringType.Short): string {
+    if (stringType === CardStringType.Char) {
+      return '_' + this.map((card) => card.toString(stringType)).join('');
+    }
     return this.map((card) => card.toString(stringType)).join(', ');
   }
 }
@@ -97,6 +114,7 @@ class Card {
   public static readonly Suits = CardSuits;
   public static readonly StringType = CardStringType;
 
+  private static chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
   private static emojiSuits = ['♥', '♠', '♦', '♣'];
   private static shortSuits = ['h', 's', 'd', 'c'];
   private static longSuits = ['hearts', 'spades', 'diamonds', 'clubs'];
@@ -149,6 +167,8 @@ class Card {
           ' of ' +
           this.toString(Card.StringType.LongSuit)
         );
+      case Card.StringType.Char:
+        return Card.chars[this.num];
       case Card.StringType.ShortSuit:
         return Card.shortSuits[this.suit];
       case Card.StringType.LongSuit:

src/deck.ts

@@ -1,4 +1,4 @@
-import Card, { CardJSON } from './card';
+import Card, { CardJSON, Cards } from './card';
 import { shuffle, isSorted } from './arr';
 
 interface DeckJSON {
@@ -23,6 +23,12 @@ class Deck {
     return deck;
   }
 
+  public static fromString(input: string): Deck {
+    const deck = new Deck(false, 0);
+    deck.cards = new Cards(input);
+    return deck;
+  }
+
   public shuffle(): void {
     shuffle(this.cards);
   }
@@ -49,6 +55,10 @@ class Deck {
 
     return cards;
   }
+
+  public toString(stringType = Card.StringType.Char): string {
+    return new Cards(this.cards).toString(stringType);
+  }
 }
 
 export default Deck;