javascript - array.concat() 的问题

Question

我正在尝试使用递归调用来连接返回数组

这个问题的方向是:接收到数据流，需要将其反转。

每段长度为8位，意味着这些段的顺序需要颠倒，例如:

11111111 00000000 00001111 10101010 (byte1) (byte2) (byte3) (byte4)应该变成:

10101010 00001111 00000000 11111111 (byte4) (byte3) (byte2) (byte1)总位数总是 8 的倍数。

尝试不同的事物组合真的...

function dataReverse(data) {
  //split incoming array into array values consisting of 8 numbers each.
  //var octGroups = data.length / 8;
  var result = [];
  //recursive call
  function shuffler(array){
    let input = array;
    //base case
    if(input.length === 0){
      return result;
    } else {
      //concat result with 8 values at a time
      let cache = input.splice(-8,8);
      result.concat(cache);
      return shuffler(input);
    }
    return result;
  }
  
  
  
  
  
  var reversed = shuffler(data);
//base case is if data.length === 0 return result else
//reverse iterate through array, concating to new return array
//return result
  return reversed;
}

console.log(dataReverse([1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,0,1,0,1,0,1,0]));

预计会反转输入数组，从末尾开始一次连接一个包含 8 个值的结果数组，但不会反转数字的顺序。

我上面的尝试返回了一个零长度数组。我做错了什么？

Answer 1

使用join代替concat

function dataReverse(data) {
  //split incoming array into array values consisting of 8 numbers each.
  //var octGroups = data.length / 8;
  var result = [];
  //recursive call
  function shuffler(array) {
    let input = array;
    //base case
    if (input.length === 0) {
      return result;
    } else {
      //concat result with 8 values at a time
      let cache = input.splice(-8, 8);
      result.push(cache.join(''));
      return shuffler(input);
    }
    return result;
  }


  var reversed = shuffler(data);
  //base case is if data.length === 0 return result else
  //reverse iterate through array, concating to new return array
  //return result
  return reversed;
}

console.log(dataReverse([1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0]));