如何檢查值是否在具有基于另一個陣列的物件的陣列中

在JavaScript我想，以檢查是否值myPointID從b是一個。

我試過了：

console.log(a.points.filter((f) => f.myPoint.myPointID === b.myPointID)); 

我似乎無法找出正確的方法。

var a = [
    {
        "id": "1",
        "name": "sample1",
        "points": [
            {
                "pointID": "12",
                "name": "sample point",
                "myPoint": {
                    "myPointID": "12345",
                    "name": "sample my point",
                    "form": "form1"
                }
            }
        ]
    },
    {
        "id": "2",
        "name": "sample2",
        "points": [
            {
                "pointID": "123",
                "name": "sample point2",
                "myPoint": {
                    "myPointID": "123456",
                    "name": "sample my point2",
                    "form": "form2"
                }
            }
        ]
    },
    {
        "id": "3",
        "name": "sample3",
        "points": [
            {
                "pointID": "123",
                "name": "sample point2",
                "myPoint": {
                    "myPointID": "123456",
                    "name": "sample my point2",
                    "form": "form2"
                }
            }
        ]
    }
];

var b = [
    {myPointID: "123456", desc: "sm"},
    {myPointID: "123456", desc: "sm2"}
];

uj5u.com熱心網友回復：

您可以從過濾器陣列中獲取想要的 id 并使用嵌套回圈檢查資料。

const
    data = [{ id: "1", name: "sample1", points: [{ pointID: "12", name: "sample point", myPoint: { myPointID: "12345", name: "sample my point", form: "form1" } }] }, { id: "2", name: "sample2", points: [{ pointID: "123", name: "sample point2", myPoint: { myPointID: "123456", name: "sample my point2", form: "form2" } }] }, { id: "3", name: "sample3", points: [{ pointID: "123", name: "sample point2", myPoint: { myPointID: "123456", name: "sample my point2", form: "form2" } }] }],
    filter = [{ myPointID: "123456", desc: "sm" }, { myPointID: "123456", desc: "sm2" }],
    ids = new Set(filter.map(({ myPointID }) => myPointID));

console.log(data.filter(({ points }) =>
    points.some(({ myPoint: { myPointID } }) => ids.has(myPointID))
));

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

uj5u.com熱心網友回復：

對于使用Array.prototype.reduce() 時是否存在任何myPointIDfrom ，這將回傳 true 或 falseba

let b_myPointIds = b.map(function(x){ return x.myPointID})
let reducer = function(accumulator, aChild){                  // 'value' is an array item from a
    if (accumulator) {                                        // if prev iteration returned true then shortcircuit
        return accumulator;
    } 
    
    for(let i = 0; i<aChild.points.length;   i){
        if(b_myPointIds.includes(aChild.points[i].myPoint.myPointID)){
            return true;               
        }
    }
    return false;
}
let isMyPointIdInA = a.reduce(reducer, false);               // false is initial value of 'isMyPointIdInA'     
console.log(isMyPointIdInA);

顯示代碼片段

var a = [
    {
        "id": "1",
        "name": "sample1",
        "points": [
            {
                "pointID": "12",
                "name": "sample point",
                "myPoint": {
                    "myPointID": "12345",
                    "name": "sample my point",
                    "form": "form1"
                }
            }
        ]
    },
    {
        "id": "2",
        "name": "sample2",
        "points": [
            {
                "pointID": "123",
                "name": "sample point2",
                "myPoint": {
                    "myPointID": "123456",
                    "name": "sample my point2",
                    "form": "form2"
                }
            }
        ]
    },
    {
        "id": "3",
        "name": "sample3",
        "points": [
            {
                "pointID": "123",
                "name": "sample point2",
                "myPoint": {
                    "myPointID": "123456",
                    "name": "sample my point2",
                    "form": "form2"
                }
            }
        ]
    }
];

var b = [
    {myPointID: "123456", desc: "sm"},
    {myPointID: "123456", desc: "sm2"}
];


//--------------------------------------------------------------------------

let b_myPointIds = b.map(function(x){ return x.myPointID})
let reducer = function(accumulator, aChild){                  // 'value' is an array item from a
    if (accumulator) {                                        // if prev iteration returned true then shortcircuit
        return accumulator;
    } 

    for(let i = 0; i<aChild.points.length;   i){
        if(b_myPointIds.includes(aChild.points[i].myPoint.myPointID)){
            return true;                                     // set accumulator to true
        }
    }
    return false;
}
let isMyPointIdInA = a.reduce(reducer, false);               // false is initial value of 'isMyPointIdInA'     
console.log(isMyPointIdInA);

標籤：javascript json

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