How to assign the DataFrame, created in an async function which reads a csv file using danfo.js, to a global variable outside of this async function?

Question

[What I want to do]

1. use danfo.js to read a csv file from a url
2. assign the danfo.js DataFrame (similar to that in pandas) as created above to a global variable, so that I can use it somewhere else for other purpose, such as plotting charts.

[What I did] I created an async function to read the csv file:

const url =
    "https://raw.githubusercontent.com/plotly/datasets/master/finance-charts-apple.csv"; 

async function readCSV(url) {
    try {
        const df = await dfd.readCSV(url);

        console.log("df describe: ");
        df.describe().print(); // print df describe as a table

    } catch (error) {
        console.error(error);
    }
}

readCSV(url)

[What's the issue] It seems that the DataFrame created from reading the csv file can only be used inside this async function.

[My question] How to get the DataFrame out of the async function and assign it to a global variable?

[What I tried] I also tried the following by adding a return in the readCSV function. But this seems cumbersome because every time I want to use the DataFrame, I have to call the function to read the csv again.

async function readCSV(url) {
    try {
        const df = await dfd.readCSV(url);
        return df;
    } catch (error) {
        console.error(error);
    }
}

readCSV(url).then((df) => {
    console.log("df head: ");
    df.head().print(); 
});

[reference I read] How to return values from async functions using async-await from function? How do I return the response from an asynchronous call?