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

Question

I a trying to display a warning to the user, I split an array, and always use the 0 and 1 position values, sometimes the array might contain a value in position 2, not all the time.

I would like to build the message string to show the value of arr[2] if it's there, or only arr[0], and arr[1] if not arr[2] is present.

I tried to do it this manner:

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.';

Just by looking at it and seeing the redundancy, I know I am doing it wrong, or not best practice. But somehow it works, but only whne arr[2] has a value because the part in which I check for arr[2] length, if not there, then the code breaks.

Is it possible someone could show me how to correctly use the ternary operator to achieve this goal?

Thank you kindly, 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.`;

Pull the prefix out and derive it based on the number of elements in the array. Also, if you change your string to be a string literal instead, you can have literal new lines in your string, rather than \\n and have it be much more readable.