set-game.js

const NUM_CARD_PROP_OPTIONS = 3;
const NUM_CARD_PROPS = 4
const BOARD_SIZE = 12;
const SET_SIZE = 3;

export const getCardProp = () => Math.floor(Math.random() * NUM_CARD_PROP_OPTIONS)
export const getCard = () => new Array(NUM_CARD_PROPS).fill().map(getCardProp)
export const getBoard = () => new Array(BOARD_SIZE).fill().map(getCard)

export  const combinations = (arr = [], len) => {
    if(len === 1) {
        return arr.map(a => [a]);
    }

    if(arr.length === 0) {
        console.error('arr is empty')
    }

    let result = [] 
    for(let i = 0; i < arr.length; i++) {
        result = [...result, ...combinations([...arr.filter((v, idx) => i != idx)], len - 1).map(a => [arr[i], ...a])];
    }
    
    return result;

}

export const isSet = (cards) => {
    for(let i = 0; i < NUM_CARD_PROPS; i++) {
        const arr = new Array(NUM_CARD_PROP_OPTIONS).fill(0)
        for(let j = 0; j < cards.length; j++) {
            arr[cards[j][i]] += 1;
        }

        if(!arr.every(e => e === 1) && !arr.find(e => e === cards.length)) {
            return false;
        }
    }

    return cards.length > 0;
}

export const findSet = (board = []) => 
    combinations(board.map((_, i ) => i), SET_SIZE)
        .find(testIndexes => isSet(testIndexes.map(j => board[j]))) || []


export const playGame = () => {
    do {
        const board = getBoard();
        console.log('board:', board)

        const foundSet = findSet(board)
        if(foundSet) {
            console.log('found set at', foundSet)
            console.log(foundSet.map(i => board[i]))
            break;
        } 

        console.log('no set \n')


    } while (true)
}