题解 | #子字符串频次#
https://www.nowcoder.com/practice/053caf9d4d9d449bb45a6b02a572f71b
利用正则
const _searchStrIndexOf = (str, target) => {
// 补全代码
let rxg = new RegExp(`${target}`, "g")
let test = str.match(rxg)
return test.length
}