正则

// \n换行符不能被.匹配
console.log(/foo.bar/.test("fooabar")); // true
console.log(/foo.bar/.test("foo\nbar")); // false
// dotAll
console.log(/foo.bar/su.test("foo\nbar")); // true
const re = /foo.bar/gisu;
console.log(re.dotAll); // true
console.log(re.flags); // gisu
// const t = "2020-03-28".match(/(\d{4})-(\d{2})-(\d{2})/);
// console.log(t[1]); // 2020
// console.log(t[2]); // 03
// console.log(t[3]); // 28
// 命名分组捕获
const t = "2020-03-28".match(/(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/);
console.log(t.groups.year); // 2020
console.log(t.groups.month); // 03
console.log(t.groups.day); // 28
// 断言
let test = "hello world";
console.log(test.match(/hello(?=\sworld)/));
// ?<= 等于 ?<!不等于
console.log(test.match(/(?<=hello\s)world/));
console.log(test.match(/(?<!helle\s)world/));