1、默认值
var obj = undefined || {};
console.log(obj);//输出:{}
2、数组利用Set去重
var arr = [...new Set([1, 2, 3, 3])];
console.log(arr); //输出:[1, 2, 3]
3、利用Array.join()批量生成重复的内容
var repeat = 3;//数组大小
var content = new Array(repeat).join("hello word!");
console.log(content);//输出:hello word!hello word!,注意此处重复生成的次数为repeat-1
4、利用Array.filter(Boolean)过滤数组中的假值
var res = [1,2,undefined,false,true,0,'0'].filter(Boolean);
console.log(res);//输出:[1, 2, true, "0"]
5、利用修改Array.length的值删除数组尾部元素
var res = [1,2,undefined,false,true,0,'0'].filter(Boolean);
console.log(res);//输出:[1, 2, true, "0"]
res.length = 2;
console.log(res);//输出:[1, 2]
6、利用JSON.stringify格式化json对象
var obj = {a:1,b:{c:3},d:4,e:{aa:1,bb:2}};
var formatStr = JSON.stringify(obj, null, 4);
console.log(formatStr);//输出:
{
"a": 1,
"b": {
"c": 3
},
"d": 4,
"e": {
"aa": 1,
"bb": 2
}
}