JavaScript相当于MySQL函数SUBSTRING_INDEX()

Question

MySQL中的 SUBSTRING_INDEX()在指定的分隔符出现次数之前返回字符串中的子字符串.

JavaScript中是否有任何等效功能？我需要执行相同的操作..但是在JavaScript中的字符串值.

Answer 1

MySQL的:

SELECT SUBSTRING_INDEX('www.stackoverflow.com', '.', 1) result;
+--------+
| result |
+--------+
| www    |
+--------+
1 row in set (0.00 sec)

SELECT SUBSTRING_INDEX('www.stackoverflow.com', '.', 2) result;
+-------------------+
| result            |
+-------------------+
| www.stackoverflow |
+-------------------+
1 row in set (0.00 sec)

JavaScript的:

function substringIndex (input, delimiter, index) {
  var arr = input.split(delimiter);
  arr.splice(index, arr.length - index);
  return arr.join(delimiter);
}

console.log(substringIndex('www.stackoverflow.com', '.', 1)); 
// www

console.log(substringIndex('www.stackoverflow.com', '.', 2)); 
// www.stackoverflow