deck-example.js

/*
 * list all possible combinations/boards of 5 cards, chosen from a
 * deck of 52 cards (13 different card values, 4 different suits),
 * without repetition/replacement.
 */

let log = console.log
    , spades = 'A♠ K♠ Q♠ J♠ T♠ 9♠ 8♠ 7♠ 6♠ 5♠ 4♠ 3♠ 2♠ '
    , clubs = 'A♣ K♣ Q♣ J♣ T♣ 9♣ 8♣ 7♣ 6♣ 5♣ 4♣ 3♣ 2♣ '
    , diamonds = 'A♦ K♦ Q♦ J♦ T♦ 9♦ 8♦ 7♦ 6♦ 5♦ 4♦ 3♦ 2♦ '
    , hearts = 'A♥ K♥ Q♥ J♥ T♥ 9♥ 8♥ 7♥ 6♥ 5♥ 4♥ 3♥ 2♥'
    , deck = ( spades + clubs + diamonds + hearts ).split( ' ' )
    , dlen = deck.length
    , Geco = require( '../' )
    // get k cards, 3 for simulate all possible flops, 5 for boards ..
    , cards = 5
    // get the iterable generator
    , iter = Geco.gen( deck.length, cards, deck )
    , cnt = 0
    , board = null
    // get total number of combinations
    , tot = ( () => {
        let i = 0
            , f1 = 1
            , f2 = 1
            ;
        for ( ; i < cards; ++i ) {
            f1 *= dlen - i;
            f2 *= cards - i;
        }
        return ( f1 / f2 );
    } ) ()
    , stime = Date.now()
    , etime = -1
    ;

for ( board of iter )
    log( ` (${ ++cnt }): ${board} [${ ( 100 * cnt / tot ).toFixed( 5 ) } %]` );

etime = ( ( Date.now() - stime ) / 1000 ).toFixed( 2 );

log( `\n- time elapsed: ${ etime } secs` );