I am a beginner in javascript and react. I’m trying to refactor the class component into a functional one (Rules for Yahtzee game scoring).
This is class component:
/** Rule for Yahtzee scoring.
*
* This is an "abstract class"; the real rules are subclasses of these.
* This stores all parameters passed into it as properties on the instance
* (to simplify child classes so they don't need constructors of their own).
*
* It contains useful functions for summing, counting values, and counting
* frequencies of dice. These are used by subclassed rules.
*/
class Rule {
constructor(params) {
// put all properties in params on instance
Object.assign(this, params);
}
sum(dice) {
// sum of all dice
return dice.reduce((prev, curr) => prev + curr);
}
freq(dice) {
// frequencies of dice values
const freqs = new Map();
for (let d of dice) freqs.set(d, (freqs.get(d) || 0) + 1);
return Array.from(freqs.values());
}
count(dice, val) {
// # times val appears in dice
return dice.filter(d => d === val).length;
}
}
/** Given a sought-for val, return sum of dice of that val.
* Used for rules like "sum of all ones"*/
class TotalOneNumber extends Rule {
evalRoll = dice => {
return this.val * this.count(dice, this.val);
};
}
/** Given a required # of same dice, return sum of all dice.
* Used for rules like "sum of all dice when there is a 3-of-kind"*/
class SumDistro extends Rule {
evalRoll = dice => {
// do any of the counts meet of exceed this distro?
return this.freq(dice).some(c => c >= this.count) ? this.sum(dice) : 0;
};
}
/** Check if full house (3-of-kind and 2-of-kind) */
class FullHouse extends Rule {
evalRoll = dice => {
const freqs = this.freq(dice);
return freqs.includes(2) && freqs.includes(3) ? this.score : 0;
};
}
/** Check for small straights. */
class SmallStraight extends Rule {
evalRoll = dice => {
const d = new Set(dice);
// straight can be 234 + either 1 or 5
if (
(d.has(2) && d.has(3) && d.has(4) && d.has(5) && d.has(2)) ||
d.has(5)
) {
return this.score;
}
// or 345 + either 2 or 6
if ((d.has(3) && d.has(4) && d.has(5) && d.has(2)) || d.has(6)) {
return this.score;
}
return 0;
};
}
/** Check for large straights. */
class LargeStraight extends Rule {
evalRoll = dice => {
const d = new Set(dice);
// large straight must be 5 different dice & only one can be a 1 or a 6
return d.size === 5 && (!d.has(1) || !d.has(6)) ? this.score : 0;
};
}
/** Check if all dice are same. */
class Yahtzee extends Rule {
evalRoll = dice => {
// all dice must be the same
return this.freq(dice)[0] === 5 ? this.score : 0;
};
}
// ones, twos, etc score as sum of that value
const ones = new TotalOneNumber({ val: 1, description: '1 point per 1' });
const twos = new TotalOneNumber({ val: 2, description: '2 points per 2' });
const threes = new TotalOneNumber({ val: 3, description: '3 points per 3' });
const fours = new TotalOneNumber({ val: 4, description: '4 points per 4' });
const fives = new TotalOneNumber({ val: 5, description: '6 points per 5' });
const sixes = new TotalOneNumber({ val: 6, description: '6 points per 6' });
// three/four of kind score as sum of all dice
const threeOfKind = new SumDistro({
count: 3,
description: 'Sum all dice if 3 are the same'
});
const fourOfKind = new SumDistro({
count: 4,
description: 'Sum all dice if 4 are the same'
});
// full house scores as flat 25
const fullHouse = new FullHouse({
score: 25,
description: '25 points for full house'
});
// small/large straights score as 30/40
const smallStraight = new SmallStraight({
score: 30,
description: '30 points for small straight'
});
const largeStraight = new LargeStraight({
score: 40,
description: '40 points for large straight'
});
// yahtzee scores as 50
const yahtzee = new Yahtzee({
score: 50,
description: '30 points for yahtzee'
});
// for chance, can view as some of all dice, requiring at least 0 of a kind
const chance = new SumDistro({ count: 0, description: 'Sum of all dice' });
export {
ones,
twos,
threes,
fours,
fives,
sixes,
threeOfKind,
fourOfKind,
fullHouse,
smallStraight,
largeStraight,
yahtzee,
chance
};
This is my non working refactored code:
// put all properties in params on instance
Object.assign(params);
function sum(dice) {
// sum of all dice
return dice.reduce((prev, curr) => prev + curr);
}
function freq(dice) {
// frequencies of dice values
const freqs = new Map();
for (let d of dice) freqs.set(d, (freqs.get(d) || 0) + 1);
return Array.from(freqs.values());
}
function count(dice, val) {
// # times val appears in dice
return dice.filter(d => d === val).length;
}
/** Given a sought-for val, return sum of dice of that val.
*
* Used for rules like "sum of all ones"
*/
const TotalOneNumber = {
evalRoll: (dice, val) => {
return val * count(dice, val);
}
}
/** Given a required # of same dice, return sum of all dice.
*
* Used for rules like "sum of all dice when there is a 3-of-kind"
*/
const sumDistro = {
evalRoll: dice => {
// do any of the counts meet of exceed this distro?
return freq(dice).some(c => c >= count) ? sum(dice) : 0;
}
}
/** Check if full house (3-of-kind and 2-of-kind) */
const fullHouse = {
evalRoll: (dice, score) => {
const freqs = freq(dice);
return freqs.includes(2) && freqs.includes(3) ? score : 0;
}
}
/** Check for small straights. */
const smallStraight = {
evalRoll: (dice, score) => {
const d = new Set(dice);
// straight can be 234 + either 1 or 5
if (
(d.has(2) && d.has(3) && d.has(4) && d.has(5) && d.has(2)) ||
d.has(5)
) {
return score;
}
// or 345 + either 2 or 6
if ((d.has(3) && d.has(4) && d.has(5) && d.has(2)) || d.has(6)) {
return score;
}
return 0;
}
}
/** Check for large straights. */
const largeStraight = {
evalRoll: (dice, score) => {
const d = new Set(dice);
// large straight must be 5 different dice & only one can be a 1 or a 6
return d.size === 5 && (!d.has(1) || !d.has(6)) ? score : 0;
}
}
/** Check if all dice are same. */
const yahtzee = {
evalRoll: (dice, score) => {
// all dice must be the same
return freq(dice)[0] === 5 ? score : 0;
}
}
// ones, twos, etc score as sum of that value
const ones = new TotalOneNumber({ val: 1, description: '1 point per 1' });
const twos = new TotalOneNumber({ val: 2, description: '2 points per 2' });
const threes = new TotalOneNumber({ val: 3, description: '3 points per 3' });
const fours = new TotalOneNumber({ val: 4, description: '4 points per 4' });
const fives = new TotalOneNumber({ val: 5, description: '6 points per 5' });
const sixes = new TotalOneNumber({ val: 6, description: '6 points per 6' });
// three/four of kind score as sum of all dice
const threeOfKind = new sumDistro({
count: 3,
description: 'Sum all dice if 3 are the same'
});
const fourOfKind = new sumDistro({
count: 4,
description: 'Sum all dice if 4 are the same'
});
// full house scores as flat 25
const FullHouse = new FullHouse({
score: 25,
description: '25 points for full house'
});
// small/large straights score as 30/40
const SmallStraight = new SmallStraight({
score: 30,
description: '30 points for small straight'
});
const LargeStraight = new LargeStraight({
score: 40,
description: '40 points for large straight'
});
// yahtzee scores as 50
const Yahtzee = new Yahtzee({
score: 50,
description: '30 points for yahtzee'
});
// for chance, can view as some of all dice, requiring at least 0 of a kind
const chance = new sumDistro({ count: 0, description: 'Sum of all dice' });
export {
ones,
twos,
threes,
fours,
fives,
sixes,
threeOfKind,
fourOfKind,
fullHouse,
smallStraight,
largeStraight,
yahtzee,
chance,
};
Unfortunately, I am struggling to make this work, can someone help me, what am I doing wrong here?
)
