字符串String

生成随机的id

// 接收一个长度
const RandomId = len => Math.random().toString(36).substr(3, len);

// eg
RandomId(10);

生成随机颜色值

const RandomColor = () => "#" + Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, "0");
const color = RandomColor();

操作URL查询参数

const params = new URLSearchParams(location.search.replace(/\?/ig, "")); // location.search = "?name=young&sex=male"
params.has("young"); // true
params.get("sex"); // "male"

首字母转成大写

const capitalize = ([first, ...rest]) => first.toUpperCase() + rest.join('');
  
capitalize('fooBar'); // 'FooBar'
capitalize('fooBar', true); // 'FooBar'

每个单词首字母转换成大写字母

const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase());

capitalizeEveryWord('hello world!'); // 'Hello World!'