Steamroller JavaScript代码如何发生

Question

愉悦描述我递归功能如何在最终结果中弄平阵列。主要请在“如果”部分中描述

function steamrollArray(arr) {
  let answer = [].concat(...arr);
  console.log(answer)
  if(answer.some(Array.isArray)){
    return steamrollArray(answer);
  }
  return answer
}

let result = steamrollArray([1, [2], [3, [[4]]]]);
// console.log(result)

Answer 1

添加了console.log，以帮助了解递归的工作原理。引入了变量idx，以帮助跟踪递归级别。

function steamrollArray(arr, idx=0) {
  console.log('bgn--> recursion # ', idx);
  console.log('arr: ', JSON.stringify(arr));
  let answer = [].concat(...arr);
  console.log(
    'computed answer: ', JSON.stringify(answer)
  );
  if(answer.some(Array.isArray)){
    // "answer" has an array, so recurse to next level
    console.log(
      'at least ONE elt in "answer" is an array\n',
      '--> making recursive call from recursion #: ',
      idx
    );
    return steamrollArray(answer, idx+1);
  };
  console.log(
    'no elt in "answer" is an array\n',
    'no more recursion from recursion #: ', idx,
    ' answer: ', answer.join(),
    ' has ZERO arrays ...'
  );
  return answer;
}

let result = steamrollArray([1, [2], [3, [[4]]]]);
// console.log(result)

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