如何构建消息字符串，在存在时使用数组值

Question

我试图向用户显示警告，我拆分了一个数组，并始终使用 0 和 1 位置值，有时数组可能包含位置 2 的值，但并非始终如此。

我想构建消息字符串以显示 arr[2] 的值（如果存在），或者仅显示 arr[0] 和 arr[1]（如果不存在 arr[2]）。

我试过这样做：

strWarningMsg =

    arr[2].length > 0 ? arr[1] + arr[2] + ' meeting, ' + '\nscheduled for: ' + arr[0].replace(/ +/g, " ")
    + '; data has been already uploaded.\n' + '\n Changes to the existing data could potentially invalidate any existing registration(s). Make sure to use the Cross-Reference file template before you attempt a new upload for this meeting.'
    + '\n\nPress OK to overwrite the existing Cross Reference List, or\nPress Cancel to abort the operation.'
   : arr[1] + ' meeting, ' + '\nscheduled for: ' + arr[0].replace(/ +/g, " ")
    + '; data has been already uploaded.\n' + '\n Changes to the existing data could potentially invalidate any existing registration(s). Make sure to use the Cross-Reference file template before you attempt a new upload for this meeting.'
    + '\n\nPress OK to overwrite the existing Cross Reference List, or\nPress Cancel to abort the operation.';

只要看看它并看到冗余，我就知道我做错了，或者不是最佳实践。但不知何故它起作用了，但只有当 arr[2] 有一个值时，因为我检查 arr[2] 长度的部分，如果不存在，那么代码就会中断。

有人可以告诉我如何正确使用三元运算符来实现这个目标吗？

谢谢你， Erasmo.

Answer 1

const prefix = (arr.length > 2 ? arr[1] + arr[2] : arr[1]);
const strWarningMsg = `${prefix} meeting,
scheduled for: ${arr[0].replace(/ +/g, " ")}; data has been already uploaded.

Changes to the existing data could potentially invalidate any existing registration(s). Make sure to use the Cross-Reference file template before you attempt a new upload for this meeting.

Press OK to overwrite the existing Cross Reference List, or\nPress Cancel to abort the operation.`;

把前缀拉出来，根据数组元素个数推导。此外，如果您将字符串更改为字符串文字，则可以在字符串中使用文字新行，而不是 \n 并使其更具可读性。

如何构建消息字符串，在存在时使用数组值

how to build a message string, using array values when present

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string

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