JavaScript function that converts a comma-separated value (CSV) string, into a 2D array of objects. The first row of the string is used as the title row.

/**
 * CSVToJSON
 *
 * Converts a comma-separated values (CSV) string to a 2D array of objects. The
 * first row of the string is used as the title row.
 *
 * Use `Array.prototype.slice()` and `Array.prototype.indexOf('\n')` and
 * `String.prototype.split(delimiter)` to separate the first row (title row)
 * into values. Use `String.prototype.split('\n')` to create a string for each
 * row, then `Array.prototype.map()` and `String.prototype.split(delimiter)` to
 * separate the values in each row. Use `Array.prototype.reduce()` to create an
 * object for each row's values, with the keys parsed from the title row. Omit
 * the second argument, `delimiter`, to use a default delimiter of `,`.
 *
 * @param {String} data
 * @param {String} delimiter
 * @return {Object}
 */
const CSVToJSON = (data, delimiter = ",") => {
    const titles = data.slice(0, data.indexOf("\n")).split(delimiter);
    return data
        .slice(data.indexOf("\n") + 1)
        .split("\n")
        .map(v => {
            const values = v.split(delimiter);
            return titles.reduce(
                (obj, title, index) => ((obj[title] = values[index]), obj),
                {}
            );
        });
};

//
// Compiled (ES2015)
var CSVToJSON = function CSVToJSON(data) {
    var delimiter = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : ",";
    var titles = data.slice(0, data.indexOf("\n")).split(delimiter);
    return data
        .slice(data.indexOf("\n") + 1)
        .split("\n")
        .map(function(v) {
            var values = v.split(delimiter);
            return titles.reduce(function(obj, title, index) {
                return (obj[title] = values[index]), obj;
            }, {});
        });
};

// --------------------------------------------------
// Example Usage
// --------------------------------------------------

CSVToJSON("col1,col2\na,b\nc,d"); // [{'col1': 'a', 'col2': 'b'}, {'col1': 'c', 'col2': 'd'}];
CSVToJSON("col1;col2\na;b\nc;d", ";"); // [{'col1': 'a', 'col2': 'b'}, {'col1': 'c', 'col2': 'd'}];