select random value in 2d array js code example

Example 1: pick random string from array javascript

var groceries = [
'milk',
'coriander',
'cucumber',
'eggplant'
]
let mygroceries = groceries[Math.floor(Math.random() * groceries.length)]
console.log(mygroceries)//This gives you any string from groceries

Example 2: function that takes any question and returns a randomly selected item from an array

var a = ["Roger", "Russell", "Clyde", "Egbert", "Clare", "Bobbie", "Simon", "Elizabeth", "Ted", "Caroline"];

var chooseName = function () {
    var unique = true;
    num = Math.floor(Math.random() * a.length - 5);
    name = a.splice(num,1);
    a.push(name);
}


window.addEventListener("keypress", function (e) {
    var keycode = e.keyCode;
    if (keycode == 13) {
        chooseName();
    }
}, false);