javascript闭包的缓存应用

function eater () {
                    var food = "apple";
                    var obj = {
                        eat : function () {
                            if (food != "") {
                                console.log("i‘m eating" + " " + food)
                                food = "";
                            }else {
                                console.log(‘there is nothing‘);
                            }
                        },
                        push : function (myFood) {
                            food = myFood;
                        }
                    }
                    return obj;
                }
                var eater1 = eater();
                eater1.eat();
                eater1.eat();
                eater1.push(‘banana‘);
                eater1.eat();