streaming asynchronous custom function failed to calculate time

[Edward-Zhou]

I am developing with Excel AddIn cusotm function, and I made a test with Create a streaming asynchronous custom function

If I test with return value is number, the calculation is correct, but if the return value is date, the formula in Excel cell will return #Value

Here is my test code

/** @CustomFunction
 * @description Increments the cell with a given amount at a specified interval in milliseconds.
 * @param {number} amount - The amount to add to the cell value on each increment.
 * @param {number} interval - The time in milliseconds to wait before the next increment on the cell.
 * @param {CustomFunctions.StreamingInvocation<number>} invocation - Parameter to send results to Excel
 *     or respond to the user canceling the function.
 * @returns An incrementing value.
 */
function increment(amount: number, invocation: CustomFunctions.StreamingInvocation<number>): void {
  let result = 0;
  const timer = setInterval(() => {
    result += amount;
    invocation.setResult(result);
  }, 1000);

  invocation.onCanceled = () => {
    clearInterval(timer);
  };
}
/**
 * Returns the current time
 * @returns {string} String with the current time formatted for the current locale.
 */
function currentTime() {
  return new Date();
}

/**
 * Displays the current time once a second
 * @customfunction
 * @param {CustomFunctions.StreamingInvocation<string>} invocation Custom function invocation
 */
function clock(invocation) {
  const timer = setInterval(() => {
    const time = currentTime();
    invocation.setResult(time);
  }, 1000);

  invocation.onCanceled = () => {
    clearInterval(timer);
  };
}

And there is my formula in Excel cell

B11: =SCRIPTLAB.STREAMINGFUNCTION.INCREMENT(1)
B12:=B11+10 // This will return dynamic value by B11 + 10
B13:=SCRIPTLAB.STREAMINGFUNCTION.CLOCK()
B14:=B13+10 //return "#Value"

[XuanZhouMSFT]

Thanks for waiting. The #Value should be a by-design behavior. The streaming custom funtion "clock" you are using returns a string type. With the string type, the operation "+" could not work in Excel. So it will show the #Value.