javascript - 当第二个数组为 0 时，无法在 JavaScript 中合并两个排序数组

Question

我正在尝试编写一个函数来合并两个排序的数组 a 和 b。但是，当数组 b 的值为 0 时，它只会将数组 a 显示为输出:

function mergeSortedArrays(a,b) {
  var merged = [],
  aElm = a[0],
  bElm = b[0],
  i = 1, //index for array a
  j = 1; //index for array b

  if (a.length == 0) {
    return b;
  }
  if (b.length == 0) {
    return a;
  }

  while (aElm || bElm) {
    if ((aElm && !bElm) || aElm < bElm) { //problem is that it thinks that 0 == !bElm
      merged.push(aElm);
      aElm = a[i++];
    } else {
      merged.push(bElm);
      bElm = b[j++];
    }
  }
  return merged;
}
mergeSortedArrays([2,5,6,9], [0,1,2,3,29]) //outputs [2,5,6,9]

我知道问题是因为 0 是假的，所以在 if(aElm && !bElm) 条件下，它只会不断地将 aElm 插入 merged。什么是更好的编写条件的方法，以便它将 0 识别为整数而不是不存在？

Answer 1

What would be a better way of writing the conditional so that it recognizes the 0 as a integer rather than not existing?

编写条件的更好方法是不测试数组元素是否存在，而是检查索引。

function mergeSortedArrays(a,b) {
  var merged = [],
      i = 0, //index for array a
      j = 0; //index for array b

  while (i < a.length || j < b.length) {
    if (j == b.length || a[i] < b[j]) {
      merged.push(a[i++]);
    } else {
      merged.push(b[j++]);
    }
  }
  return merged;
}