index-3.js

function dressData() {
    /**
     * One row of the data object looks like:
     * {
     *   TV: "10",
     *   Radio: "100",
     *   Newspaper: "20",
     *   "Sales": "1000"
     * }
     *
     * Hence, while adding the data points,
     * we need to parse the String value as a Float.
     */
    csvData.forEach((row) => {
        X.push(f(row.Radio));
        y.push(f(row.Sales));
    });
}

function f(s) {
    return parseFloat(s);
}