How to save a variable in .csv format in javascript? [duplicate]

I have a variable in javascript the contents of which are valid for a .csv file. I want the user to save its contents in a file of his/her choice. I do the following:

HTML

<button type="button" id="downloadCSV">Download CSV</button>

JS

$('#downloadCSV').click(function () {
    var csvContent = generateCSV(); //The function generates a valid CSV
    var encodedUri = encodeURI(csvContent);
    window.open(encodedUri);
});

This does two things that I don't want:

1. Opens another chrome tab.
2. just says 'download' in the windows pop up (Even the extension needs to be added manually). Instead of that I want it to have a default name with extension. Say foobar.csv

I have gone through similar questions like this but to no avail. How can I achieve this?