在JS数组的开头添加元素1,然后使用Array.unshift )方法在数组的开头添加一个或多个元素,并返回更改原始数组的新长度
var fruit=['apple ',' banana ',' mango']; console.log(fruit.unshift ) (Orange ); //4console.log(fruit ); //['orange ',' apple ',' banana ',' mango']'] 2、扩展运算符(…) var arr1=['apple ',' banana ',' mango '; var arr2=['orange ', arr1]; console.log(arr2; //['orange ',' apple ',' banana ',' mango'] 3,Aarry.concat )方法连接两个或多个数组,并返回新数组而不更改原始数组
var arr3=['aaa']; console.log(arr3.concat ) arr2); //['aaa ',' orange ',' apple ',' banana ',' mango']console.log(arr2); //['orange ',' apple ',' banana ',' mango']