JSFiddle - React, Tailwind, and code Playground

JavaScript

var groceries = getGroceries();
printGroceries(groceries);

function getGroceries() {
    var canExit = false;
    var items = [];
    var item = null;

    do {
        if (item !== null)
            items.push(item)
        item = prompt("Enter an item to add to the grocery list (enter \‘q\’ to quit):");
    } while (item != 'q' && item != 'Q') 

    canExit = true;
    return items;
}

function printGroceries(groceryItems) {
    var msg = '';

    if (groceryItems.length > 0)
        for(var i = 0; i < groceryItems.length; i++)
            msg += '<p>' + groceryItems[i] + '</p>';
    else
        msg = '<p>Sorry dude, your list is empty!</p>';

    document.getElementsByTagName('body')[0].innerHTML = '<h1>My Grocery List</h1><p>Here\'s your grocery list:</p>' + msg;
}