[Bug]: Console does not clear after test when using --watch

[NicholasJohn16]

Version

29.7.0

Steps to reproduce

Run tests in watch mode on Windows 11 PC with Powershell or other terminal.

Expected behavior

The console should clear between re-runs when using --watch.

Actual behavior

The console does not clear between re-runs.

Additional context

I've attempted to get this to work on Command Prompt, Powershell v5.1, and Powershell v7.4, and it won't clear output. This appears to be related to #5251. If I change the CLEAR constant back to it's previous value for Windows the screen clears as it should.

Environment

System:
  OS: Windows 11
  CPU (8) Intel
Binaries:
  Node: 18.17.0
  npm: 9.6.7
npmPackages:
  jest: 29.7.0

[mrazauskas]

Interesting. The change you are pointing to is six years old. Hard to believe nobody complained for so long.

For fun, I installed Powershell 7.4.2 on macOS via Homebrew. Both of the following patterns work as expected (I removed the isWindows check for testing):

jest/packages/jest-util/src/specialChars.ts

Lines 18 to 20 in 654dbd6

	export const CLEAR = isWindows
	? '\u001B[2J\u001B[0f'
	: '\u001B[2J\u001B[3J\u001B[H';

Hard to say why isWindows check was needed here. I doubt, if, for example, VS Code terminal has different implementation for Windows and macOS.

Note that \x1Bc is very likely interpreted as reset, not clear. There is no single specification, but many implementations are pointing to VT100: https://vt100.net/docs/vt510-rm/RIS.html.