Get stats of an array of objects (not nested)

js_array_stats.js

const COUNT_REST_NAME = "other+"

function getColumnsFromJson(json) {
    return [...new Set(json.reduce(function (keys, element) {
        for (let key in element) {
            keys.push(key);
        }
        return keys;
    }, []))];
}
function jsonStats(json, columns, specificsValues) {
    let allColumns = getColumnsFromJson(json)
    columns ??= allColumns
    let stats = {}
    specificsValues ??= {}
    for (const column of columns) {
        if (allColumns.includes(column)) {
            if (specificsValues.hasOwnProperty(column)) {
                let countedValues = specificsValues[column];
                let columnStats = {}
                for (const jsonElement of json) {
                    let jsonColumnValue = jsonElement[column]
                    if (countedValues.includes(jsonElement[column])) {
                        columnStats[jsonColumnValue] = (columnStats[jsonColumnValue] || 0) + 1
                    } else if (countedValues.includes(COUNT_REST_NAME)) {
                        columnStats[COUNT_REST_NAME] = (columnStats[COUNT_REST_NAME] || 0) + 1
                    }
                }
                stats[column] = columnStats;
            } else {
                stats[column] = json.reduce(function (sums, entry) {
                    sums[entry[column]] = (sums[entry[column]] || 0) + 1;
                    return sums;
                }, {});
            }
        }
    }
    return stats
}

// examples:
let data = [
    {id:"1","name":"Test","isGood":true},
    {id:"2","name":"Test 1","isGood":true},
    {id:"3","name":"Test 2","isGood":false},
    {id:"4","name":"Test 3","isGood":false},
    {id:"4","name":"Test 3","isGood":true},
    {id:"4","name":null,"isGood":true},
];
console.log(jsonStats(data))
/*
{
    "id": {
        "1": 1,
        "2": 1,
        "3": 1,
        "4": 3
    },
    "name": {
        "Test": 1,
        "Test 1": 1,
        "Test 2": 1,
        "Test 3": 2,
        "null": 1
    },
    "isGood": {
        "true": 4,
        "false": 2
    }
}
*/


console.log(jsonStats(data, ["name", "isGood"]))
/*
{
    "name": {
        "Test": 1,
        "Test 1": 1,
        "Test 2": 1,
        "Test 3": 2,
        "null": 1
    },
    "isGood": {
        "true": 4,
        "false": 2
    }
}
*/


console.log(jsonStats(data, ["name", "isGood"],{"name":[null,COUNT_REST_NAME]}))
/*
{
    "name": {
        "other+": 5,
        "null": 1
    },
    "isGood": {
        "true": 4,
        "false": 2
    }
}
*/