Random select array item without duplicates without removing items (JavaScript)

Question

I have seen many questions concerning randomly selecting array items without repeating. However, most of them are answered by using the splice method. But this removes items

Answer 1

I don't get very well what you're trying to achieve, but here's one way I'd get random items once

var letters = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N"];
var getRandom = (function (array) {
    var notGivenItems = array.map(function (el) {return el;}),
    var getIndex = function () {
      return Math.floor(Math.random() * notGivenItems.length);
    };

    return function () {
        if (notGivenItems.length === 0) {
            return;
        }

        return notGivenItems.splice(getIndex(), 1)[0];
    };
})(letters); // items, in your case

getRandom(); // some letter
getRandom(); // some other letter
...
getRandom(); // different letters until all are given

// if the method is called more times than the array length it'll return undefined

EDIT: Improved performance due to @JLRishe comment