【Q643】如何实现 chunk 函数，数组进行分组

[shfshanyue]

示例如下：

// => [[1, 2, 3], [4, 5, 6], [7]]
chunk([1, 2, 3, 4, 5, 6, 7], 3)

[shfshanyue]

function chunk (list, size) {
  const l = []
  for (let i = 0; i < list.length; i++ ) {
    const index = Math.floor(i / size)
    l[index] ??= [];
    l[index].push(list[i])
  }
  return l
}

或者直接构造出每一个 chunk

function chunk(list, size) {
  const l = []

  for (let i = 0; i < list.length; i += size) {
    const chunk = list.slice(i, i + size)
    l.push(chunk)
  }

  return l
}

[haotie1990]

function chunk(array, limit) {
  limit = array.length <= limit ? array.length : limit;
  const result = [];
  while(array.length) {
    result.push(array.splice(0, limit));
  }
  return result;
}

[shfshanyue]

@haotie1990 这种实现方式很漂亮，但是有可能有副作用，当传入数组时，数组会被置空，可以先 [...array] 浅拷贝一份

[kirazZ1]

function chunk(list = [], size) {
  return list.reduce((pre, cur) => {
    const length = pre.length;
    if (length === 0 || pre[length - 1].length === size)
      return pre.concat([[cur]]);
    else {
      pre[length - 1].push(cur);
      return pre;
    }
  }, []);
}