如何遞回訪問物件值？

我有一個包含遞回物件的陣列，如下所示：

export const a: A = [
    {
        person: [
            {
                person: [{
                    person: [],
                    rating: 512,
                    justNumbers: [30, 15, 327]
                },
                    {
                        person: [
                            {
                                person: [],
                                rating: 538,
                                justNumbers: [13, 55, 643]
                            },
                            {
                                person: [],
                                rating: 964,
                                justNumbers: [314, 523, 512]
                            }
                        ],
                        rating: 413,
                        justNumbers: [876, 541, 623]
                    }],
                rating: 176,
                justNumbers: [842, 812,643]
            }
        ],
        rating: 235,
        justNumbers: [33, 565, 73]
    }];

我需要創建一個函式來以遞回方式對所有評分求和，并從每個 justNumbers 陣列中的所有數字創建一個數字陣列，該陣列按升序排序。

  const recursiveNumbersSearch = (obj: object, targetKey: string, getSum = []) => {
    const r = getSum;
    Object.keys(obj).forEach(key => {
        const value: any = obj[key];
        if (key === targetKey && typeof value !== 'object') {
            r.push(value)
        } else if (typeof value === 'object') {
            recursiveNumbersSearch(value, targetKey, r);
        }
    })
    return getSum
}

function sumArray (arr : number[]): number {
    let arraySum: number = 0;
    for (let i = 0; i<= arr.length - 1; i  ) {
        arraySum = arr[i]   arraySum;
    }
    return arraySum;
}

我這樣做了，它可以很好地計算總和，但是，幾乎沒有編譯器錯誤是：

Element implicitly has an 'any' type because expression of type 'string' can't be used to index type '{}'.
  No index signature with a parameter of type 'string' was found on type '{}'.

Argument of type 'any' is not assignable to parameter of type 'never'.

第一個用于字串：

const value: any = obj[key];

當第二個指的是：

r.push(value)

我有點困惑，因為如果我用 node 運行編譯的 JS 檔案，它會正確計算總和，但它確實指向了這兩個錯誤。

另一方面，我無法使用 recursiveNumberSearch 方法推送 justNumbers 陣列。

uj5u.com熱心網友回復：

我認為您遇到陣列問題的原因是因為您 test typeof value === 'object'，但如果value在 Array.

在這里，我寫了我認為是 的更簡單版本recursiveNumbersSearch，稱為deepProp. 它接受一個屬性名稱并回傳一個函式，該函式接受一個物件并進行深度優先遍歷，在找到的任何地方檢索命名屬性。然后我們可以使用它來對簡單的函式進行分層以對rating屬性求和或對屬性進行展平和排序justNumbers，如下所示：

const deepProp = (prop) => ({[prop]: p, ...rest}) =>
  p == undefined
    ? Object .values (rest) .flatMap (deepProp (prop))
    : [p, ... deepProp (prop) (rest)]

const a = [{person: [{person: [{person: [], rating: 512, justNumbers: [30, 15, 327]}, {person: [{person: [], rating: 538, justNumbers: [13, 55, 643]}, {person: [], rating: 964, justNumbers: [314, 523, 512]}], rating: 413, justNumbers: [876, 541, 623]}], rating: 176, justNumbers: [842, 812, 643]}], rating: 235, justNumbers: [33, 565, 73]}]

console .log (deepProp ('rating') (a))
console .log (deepProp ('justNumbers') (a))

const sum = (ns) => ns .reduce ((a, b) => a   b, 0)

const sumRatings = (o) => sum (deepProp ('rating') (o))
const organizeNumbers = (o) => deepProp ('justNumbers') (o) .flat () .sort ((a, b) => a - b)

console .log (sumRatings (a))
console .log (organizeNumbers (a))

.as-console-wrapper {max-height: 100% !important; top: 0}

恐怕我對您的 Typescript 錯誤無能為力。

標籤：javascript 数组 打字稿 递归

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