如何使用 Javascript 访问 JSON 数据集中嵌套元素的最大值

Question

I know there's a simple way to do this but I'm struggling to find it. Not sure if JSON.parse() or findIndex() or something else would be best. ultimately I need to get the highest number value of the "Number" element and concatenate that with 2 other variables to make a 12 digit Unique ID. There could be 100 "Number" values. These are incremented based on application saves and I want to get the latest save which will be represented by the highest "Number" value. This example just has 2. The structure of the JSON text is as follows:

{
    "History": [
        {
            "Id": "244725",
            "Number": "1",
            "CreateDate": "2022-07-13 11:08:17.073",
            "AppStatus": "App Status",
            "DataElements": [
                {
                    "Id": "432",
                    "Name": "App Status",
                    "Value": "App Status",
                    "GroupId": "3",
                    "CustomLabel": null
                }
            ]
        },
        {
            "Id": "244726",
            "Number": "2",
            "CreateDate": "2022-07-13 11:13:39.743",
            "AppStatus": "App Status",
            "DataElements": [
                {
                    "Id": "432",
                    "Name": "App Status",
                    "Value": "App Status",
                    "GroupId": "3",
                    "CustomLabel": null
                }
            ]
        }
    ]
}

I have a function where I want to return the 3 concatenated values as a single 12 character string.

function main(applicationNumber, historyJson) {
    const x = 1;
    const appNum = applicatinNumber.substring(1);
    const history = JSON.parse(historyJson).History.Number.length - 1;

    return applicant += appNum += history;
}

This isn't working but my bigger issue is finding the best way to return the highest logged "Number" value.

Answer 1

This would require recursion. I have used the iterate function to traverse the entire object. Along the way I searched for the maximal Number .

 var data = { "History": [{ "Id": "244725", "Number": "1", "CreateDate": "2022-07-13 11:08:17.073", "AppStatus": "App Status", "DataElements": [{ "Id": "432", "Name": "App Status", "Value": "App Status", "GroupId": "3", "CustomLabel": null }] }, { "Id": "244726", "Number": "2", "CreateDate": "2022-07-13 11:13:39.743", "AppStatus": "App Status", "DataElements": [{ "Id": "432", "Name": "App Status", "Value": "App Status", "GroupId": "3", "CustomLabel": null }] } ] } var max_Number = -Infinity; const iterate = (obj) => { if (!obj) { return; } Object.keys(obj).forEach(key => { // console.log(`key: ${key}, value: ${obj[key]}`) var value = obj[key] if (key == 'Number' && value > max_Number) { max_Number = value } if (typeof obj[key] === "object") { iterate(obj[key]) } }) } iterate(data) console.log(max_Number)