freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/steamroller.md

id, challengeType, forumTopicId, title

id	challengeType	forumTopicId	title
ab306dbdcc907c7ddfc30830	5	16079	扁平化

Description

在这道题目中，我们需要写一个数组扁平化的函数。 如果你遇到了问题，请点击帮助。

Instructions

Tests

tests:
  - text: "<code>steamrollArray([[['a']], [['b']]])</code>应该返回<code>['a', 'b']</code>。"
    testString: assert.deepEqual(steamrollArray([[["a"]], [["b"]]]), ["a", "b"]);
  - text: <code>steamrollArray([1, [2], [3, [[4]]]])</code>应该返回<code>[1, 2, 3, 4]</code>。
    testString: assert.deepEqual(steamrollArray([1, [2], [3, [[4]]]]), [1, 2, 3, 4]);
  - text: <code>steamrollArray([1, [], [3, [[4]]]])</code>应该返回<code>[1, 3, 4]</code>。
    testString: assert.deepEqual(steamrollArray([1, [], [3, [[4]]]]), [1, 3, 4]);
  - text: <code>steamrollArray([1, {}, [3, [[4]]]])</code>应该返回<code>[1, {}, 3, 4]</code>。
    testString: assert.deepEqual(steamrollArray([1, {}, [3, [[4]]]]), [1, {}, 3, 4]);

Challenge Seed

function steamrollArray(arr) {
  // I'm a steamroller, baby
  return arr;
}

steamrollArray([1, [2], [3, [[4]]]]);

Solution

function steamrollArray(arr) {
  if (!Array.isArray(arr)) {
    return [arr];
  }
  var out = [];
  arr.forEach(function(e) {
    steamrollArray(e).forEach(function(v) {
      out.push(v);
    });
  });
  return out;
}