es6 y修饰符

const s = 'aaa_aa_a'
const r1 = /a+/g
const r2 = /a+/y

console.log(r1.exec(s)) //aaa
console.log(r2.exec(s)) //aaa

console.log(r1.exec(s)) //aa
console.log(r2.exec(s)) //null,必须以a开头才行

来源：https://www.cnblogs.com/qjb2404/p/12209479.html