How to Convert CSV to JSON file and vice-versa in JavaScript ?

<script>
    const JSONToCSV = (objArray, keys) => {
        let csv = keys.join(',');
        objArray.forEach((row) => {
            let values = [];
            keys.forEach((key) => {
                values.push(row[key] || '');
            });
            csv += '\n' + values.join(',');
        });
        return csv;
    };

    const exampleJSON = [
        { 
            "date": 20210307, 
            "positives": 28756184, 
            "fatalities": 515148 
        },
        { 
            "date": 20210306, 
            "positives": 28714654, 
            "fatalities": 514309 
        },
        { 
            "date": 20210305, 
            "positives": 28654639, 
            "fatalities": 512629 
        },
        { 
            "date": 20210304, 
            "positives": 28585852, 
            "fatalities": 510408 
        },
        { 
            "date": 20210303, 
            "positives": 28520365, 
            "fatalities": 508665 
        },
        { 
            "date": 20210302, 
            "positives": 28453529, 
            "fatalities": 506216 
        },
        { 
            "date": 20210301, 
            "positives": 28399281, 
            "fatalities": 504488 
        }
    ];
    console.log(JSONToCSV(exampleJSON, 
        ['date', 'positives', 'fatalities']));
</script>

<script>
    const JSONToCSV = (objArray, keys) => [
        keys.join(','), ...objArray.map(
            row => keys.map(k => row[k] || '')
                .join(','))].join('\n');

    const exampleJSON = [
        {
            "date": 20210307,
            "positives": 28756184,
            "fatalities": 515148
        },
        {
            "date": 20210306,
            "positives": 28714654,
            "fatalities": 514309
        },
        {
            "date": 20210305,
            "positives": 28654639,
            "fatalities": 512629
        },
        {
            "date": 20210304,
            "positives": 28585852,
            "fatalities": 510408
        },
        {
            "date": 20210303,
            "positives": 28520365,
            "fatalities": 508665
        },
        {
            "date": 20210302,
            "positives": 28453529,
            "fatalities": 506216
        },
        {
            "date": 20210301,
            "positives": 28399281,
            "fatalities": 504488
        }
    ];
    console.log(JSONToCSV(exampleJSON,
        ['date', 'positives', 'fatalities']));
</script>

<script>
    const CSVToJSON = csv => {
        const lines = csv.split('\n');
        const keys = lines[0].split(',');
        return lines.slice(1).map(line => {
            return line.split(',').reduce((acc, cur, i) => {
                const toAdd = {};
                toAdd[keys[i]] = cur;
                return { ...acc, ...toAdd };
            }, {});
        });
    };

    const exampleCSV = `
            date,positives,fatalities
            20210307,28756184,515148
            20210306,28714654,514309
            20210305,28654639,512629
            20210304,28585852,510408
            20210303,28520365,508665
            20210302,28453529,506216
            20210301,28399281,504488`;
    console.log(CSVToJSON(exampleCSV));
</script>