如何使动态变量使用 .every 检查数组

Question

对于一个项目，我们需要检查一张卡中的所有数字是否与另一张卡与抽出的数字相匹配。 当使用 const checkCard = card001 进行硬编码时，它与 .every 搭配得很好。 当尝试以动态方式选择卡时，从本地存储中提取数字(例如 const card = 'card'+cardNumber)，弹出错误并显示 t.each 不是一个函数。 问题：如何使这种动态。我们希望有人能够帮助克服这个问题。

checkCard = () => {
var cardNumber = localStorage.cardNumber;

const card001 = [14, 4, 10, 8, 12, 30, 28, 23, 16, 27, 41, 35, 43, 39, 53, 57, 46, 48, 56, 74, 68, 75, 70, 66]
const card002 = [15, 13, 8, 1, 12, 26, 20, 19, 28, 24, 38, 42, 33, 41, 59, 53, 60, 55, 51, 68, 62, 71, 70, 65]
const card003 = [11, 5, 4, 13, 9, 23, 27, 16, 18, 26, 44, 38, 40, 36, 53, 47, 56, 55, 50, 69, 65, 63, 61, 74]
const previousCallList = JSON.parse(JSON.stringify(this.previousCallList));
console.log('previousCallList: ', previousCallList)
const previousCallListNumber =  JSON.parse(JSON.stringify(this.previousCallListNumber));
console.log('previousCallListNumber: ', previousCallListNumber)
//const card = 'card'+cardNumber;
const checkCard = card001
const checkDrawn = previousCallListNumber ;
const containsAll = checkCard .every(element => {
return checkDrawn.includes(element);
});
console.log(containsAll); //   ️ true
}
}

Answer 1

这两行之间是有区别的：

// Point `checkCard` to the current array stored in `card001`
const checkCard = card001
// Point `checkCard` to a string "card001"
const checkCard = "card001"

当你写'card'+cardNumber时，你正在创建一个新字符串，而不是对另一个变量的引用。

如果要根据变量的名称动态选取变量，则可以在对象上定义命名属性。例如：

const myObject = {
a: 1,
b: 2,
c: 3
};

console.log(
myObject["a"],
myObject["b"],
myObject["c"]
)

或者，使用您的数据：

const cardNumber = "001";

const card001 = [14, 4, 10, 8, 12, 30, 28, 23, 16, 27, 41, 35, 43, 39, 53, 57, 46, 48, 56, 74, 68, 75, 70, 66]
const card002 = [15, 13, 8, 1, 12, 26, 20, 19, 28, 24, 38, 42, 33, 41, 59, 53, 60, 55, 51, 68, 62, 71, 70, 65]
const card003 = [11, 5, 4, 13, 9, 23, 27, 16, 18, 26, 44, 38, 40, 36, 53, 47, 56, 55, 50, 69, 65, 63, 61, 74]
const cardVarName = "card" + cardNumber;
log(cardVarName); // This is now the string "card001", not a reference to the card001 variable

// Store the cards in an object
const cards = { card001, card002, card003 };
// Reference a card using obj[propertyName]
log(cards[cardVarName])

function log(x) { console.log(JSON.stringify(x)); }

Answer 2

如果你打算使用localStorage你需要熟悉语法，你现在拥有什么......

localStorage.cardNumber;

。应该给你一个错误。以下是两个函数，用于获取和设置数据localStorage：

/*
>key< is a string assigned as an id to stored data.
If there isn't anything stored an empty array is returned/
*/
const getLS = key => JSON.parse(localStorage.getItem(key)) || [];
/*
>key< is same as above. >data< is the value that needs to 
be stored.
*/
const setLS = (key, data) => localStorage.setItem(key, JSON.stringify(data));

请注意，LS只存储字符串，这就是为什么对数据使用JSON.parse()和JSON.stringify()的原因。在示例中 有关LS的行被注释掉，因为 SO 片段禁止它们 - 只需在正常环境中测试它们时取消注释即可。

详细信息在下面的示例中注释

// Utility function
const log = data => console.log(JSON.stringify(data));
//const getLS = key => JSON.parse(localStorage.getItem(key)) || [];
//const setLS = (key, data) => localStorage.setItem(key, JSON.stringify(data));
/*
All arrays as parameters so function can be reusable
*/
const deckA = [14, 4, 10, 8, 12, 30, 28, 23, 16, 27, 41, 35, 43, 39, 53, 57, 46, 48, 56, 74, 68, 75, 70, 66];
const deckB = [15, 13, 8, 1, 12, 26, 20, 19, 28, 24, 38, 42, 33, 41, 59, 53, 60, 55, 51, 68, 62, 71, 70, 65];
const deckC = [11, 5, 4, 13, 9, 23, 27, 16, 18, 26, 44, 38, 40, 36, 53, 47, 56, 55, 50, 69, 65, 63, 61, 74];
/**
* find match between a given number and a
* number from one or more given arrays
* @param {number} card = Number to find
* @param {arrays} cards = One or more arrays
* @returns {array<object>} Each object is
*  created like this:
*  {card: 55, row: 2, col: 17}
*  "card 55 is in the 3rd array index 17"
*/
const findMatch = (card, ...cards) => {
//const data = getLS('cards');
//data.push(card);
//setLS('cards', data);

// Gather ...cards into an array:
// [ [deckA], [deckB], [deckC] ]
const decks = [...cards];
/*
First, .map() runs through each sub-array and
.flatMap() compares each number of each sub-
array vs. card. If there's a match, return
a new object (see above) otherwise an empty
array is returned
*/
return decks.map((sub, row) => sub.flatMap((num, col) => num === card ? {card: card, row: row, col: col} : [])).flat();
};
log(findMatch(55, deckA, deckB, deckC));
log(findMatch(3, deckA, deckB, deckC));
log(findMatch(25, deckA, deckB, deckC));
log(findMatch(13, deckA, deckB, deckC));