Javascript 数组 filter,sort,Array.isArray()

过滤 filter;
排序 arr.sort;
判断是不是数组 Array.isArray();

//过滤 filter
let arr = ["hello", "word", "java", "hi"];
arr.push("hello");
console.log(arr)
for (let a of arr.filter(e => e.startsWith("h"))) {
    console.log(a)
}

// v 值; i 索引
arr.forEach((v, i) => {
    console.log(v);
})

//排序 arr.sort
arr.sort((a, b) => b.localeCompare(a));
console.log(arr)

//set 集合
let set = new Set(arr);
console.log(set);

//判断是不是数组 Array.isArray();
let a = 10;
let a2 = [10];
console.log(Array.isArray(a));
console.log(Array.isArray(a2));