reduced size and added fix for https://stackoverflow.com/questions/1293147/javascript-code-to-parse-csv-data

csvStringToArray.js

const csvStringToArray = strData =>
{
    const objPattern = new RegExp(("(\\,|\\r?\\n|\\r|^)(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|([^\\,\\r\\n]*))"),"gi");
    let arrMatches = null, arrData = [[]];
    while (arrMatches = objPattern.exec(strData)){
        if (arrMatches[1].length && arrMatches[1] !== ",")arrData.push([]);
        arrData[arrData.length - 1].push(arrMatches[2] ? 
            arrMatches[2].replace(new RegExp( "\"\"", "g" ), "\"") :
            arrMatches[3]);
    }
    return arrData;
}

What exactly is the condition for breaking out of this while statement?

When arrMatches value is no longer truthy. aka when RegExp.exec (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/exec) returns null instead of a value.