Leading zeros are stripped from Serial Monitor timestamps

[per1234]

Describe the problem

🐛 The timestamps produced by the Serial Monitor have a non-standard format resulting from stripping the leading zeros from the hours and minutes.

🐛 This is not even done consistently as the leading zeros are preserved for seconds.

To Reproduce

Steps to reproduce the behavior:

1. Upload a sketch to an Arduino board that periodically prints to the serial port. For example:

   void setup() {
     Serial.begin(9600);
   }
   void loop() {
     Serial.println("hello");
     delay(1000);
   }

2. Select Tools > Serial Monitor from the Arduino IDE menus.
3. Click the 🕙 icon ("Toggle Timestamp") that is near the top right corner of the output panel
4. Wait for a time that contains a second less than 10.
5. Look at the Serial Monitor output pane.
   🙂 Note that the leading zero on the second component of the time has not been removed.
6. Wait for a time that contains a minute less than 10.
7. Look at the Serial Monitor output pane.
   🐛 Note that the leading zero on the minute component of the time has been removed.
8. Wait for a time that contains an hour less than 10.
9. Look at the Serial Monitor output pane.
   🐛 Note that the leading zero on the hour component of the time has been removed.

23:59:58.610 -> hello
23:59:59.609 -> hello
0:0:00.620 -> hello
0:0:01.618 -> hello
0:0:02.630 -> hello

Expected behavior

Serial Monitor timestamps to be formatted the same as they were in the classic Arduino IDE:
hh:mm:ss.sss

00:05:02.590 -> hello

Arduino IDE version

Original report

2.0.0-beta.12-nightly.20211028

Last verified with

2.0.0-rc9-snapshot-5087ff0

Operating system

Windows 10

Additional context

Originally reported at:

• https://forum.arduino.cc/t/serial-monitor-changes-time-stamp-format/870115
• Serial monitor prints data with the wrong timestamp #391 (comment)

[mklemarczyk]

It is still exists in 2.0.0-rc4.

[ubidefeo]

@per1234
do we still have this issue?

[per1234]

@ubidefeo yes:

Leading zeros are still stripped from hours:

Leading zeros are still stripped from minutes:

21:9:29.101 -> hello
21:9:30.088 -> hello
21:9:31.104 -> hello

[nmzaheer]

I think the relevant code affecting this is given here

arduino-ide/arduino-ide-extension/src/browser/serial/monitor/serial-monitor-send-output.tsx

Lines 110 to 113 in df8658e

	const timestamp =
	(data.timestamp &&
	`${dateFormat(data.lines[index].timestamp, 'H:M:ss.l')} -> `) ||
	'';

Can I go ahead and submit a PR changing it to

  const timestamp =
    (data.timestamp &&
      `${dateFormat(data.lines[index].timestamp, 'HH:MM:ss.l')} -> `) ||
    '';

[per1234]

Can I go ahead and submit a PR

Hi @nmzaheer. Please do. I'll be happy to review it.

[nmzaheer]

@per1234 I've tested it on Ubuntu through WSL with my Uno board and it works.