trimStart()消除字符串头部的空格，trimEnd()消除尾部的空格
const s = ‘ abc ‘;
let a = s.trim()
let b = s.trimStart()
let c = s.trimEnd()
console.log(a)// "abc"
console.log(b) // "abc "
console.log(c)// " abc"
字符串的新方法 - trimStart()，trimEnd()
原文：https://www.cnblogs.com/blogZhao/p/12554963.html