SOURCE

function eater () {
    var food = '';
    var obj = {
        eat: function () {
            console.log('i am eatting ' + food);
        },
        push: function (myFood) {
            food = myFood;
        }
    }
    return obj
}
var eater1 = eater()
eater1.push('banana');
eater1.eat();