實例
將新項添加到數組起始位置:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.unshift("Lemon","Pineapple");
fruits 將輸出:
Lemon,Pineapple,Banana,Orange,Apple,Mango
示例來源:https://www.runoob.com/jsref/jsref-unshift.html
js操作數組/集合的其他擴展方法:https://www.cnblogs.com/dyqblog/p/5434803.html