js根据字节长度截取字符串

    splitHandle(value, lineNum) {
      if(value == null) return null;

      lineNum = lineNum * 2;//一个汉字两个长度

      var arr = value.split("");
      var newArr = new Array();
      var totalLen = 0;
      for(var i = 0; i < arr.length; i ++) {
        newArr.push(arr[i]);
        totalLen += this.getLength(arr[i]);
        if(totalLen % lineNum == 0) {
          newArr.push("<br />");
        }
      }

      return newArr.join("");
    },

    getLength(str) {
      let len = 0;
      if (str.charCodeAt(0) > 127 || str.charCodeAt(0) == 94) {
        len += 2; 
      } else {
        len ++; 
      } 
      
      return len;
    },