如何从多个不同长度的数组中创建一个新的设置长度的数组，根据重要性从每个较小的数组中提取项的数量

function createNewArray(arrays, targetLength) {
  // 确定新数组的长度
  let totalLength = arrays.reduce((sum, arr) => sum + arr.length, 0);
  let newLength = Math.min(totalLength, targetLength);

  // 创建新数组
  let newArray = new Array(newLength);
  let newArrayIndex = 0;

  // 遍历每个较小的数组，根据重要性提取项的数量
  for (let i = 0; i < arrays.length; i++) {
    let importance = Math.floor((arrays[i].length / totalLength) * newLength);
    let extractedItems = arrays[i].slice(0, importance);

    // 将提取的项放入新数组中
    for (let j = 0; j < extractedItems.length; j++) {
      newArray[newArrayIndex++] = extractedItems[j];
    }
  }

  return newArray;
}

// 示例用法
let arrays = [[1, 2, 3], [4, 5], [6, 7, 8, 9]];
let targetLength = 6;
let result = createNewArray(arrays, targetLength);
console.log(result); // 输出：[1, 2, 4, 6, 7, 8]