對于這樣一個數組 var initData=[1, "s", {a: "d", b: x => x*2} ];以下3種復制的方法都有什么區別？//method 1var data = initData;//method 2var data = initData.slice();//method 3var data=[];for (var variable in initData) {    data[variable] = initData[variable];}