如何让jest命令静默输出并通过退出码返回清晰的成败提示

Hey there! If you want to run Jest without any logs cluttering your output, but still get a clear message about whether tests passed or failed based on the command's exit code, here's how you can do it:

Unix/Linux/macOS (Bash/Zsh) #

Use this one-liner to silence all Jest output and show a simple success/fail message:

jest > /dev/null 2>&1 && echo "✅ Jest tests passed successfully!" || echo "❌ Jest tests failed!"

Let’s break this down:

• > /dev/null: Redirects all standard output (like test results, progress logs) to the null device (discards it entirely).
• 2>&1: Redirects standard error (like error messages, stack traces) to the same place as standard output, so those get discarded too.
• && echo ...: If Jest exits with a code of 0 (success), this runs the green success message.
• || echo ...: If Jest exits with any non-zero code (failure), this runs the red failure message.

Windows (PowerShell) #

For PowerShell users, the syntax is a bit different but achieves the same goal:

jest *> $null; if ($LASTEXITCODE -eq 0) { Write-Host "✅ Jest tests passed successfully!" -ForegroundColor Green } else { Write-Host "❌ Jest tests failed!" -ForegroundColor Red }

• *> $null: Discards all output (both standard and error streams) in one go.
• $LASTEXITCODE: PowerShell’s variable that stores the exit code of the last executed external command (Jest, in this case).
• The if/else block checks the exit code and prints colored messages for better visual clarity.

Add to package.json Scripts #

To make this easier to run regularly, add a dedicated script to your package.json:

{
  "scripts": {
    "test:silent": "jest > /dev/null 2>&1 && echo \"✅ Jest tests passed successfully!\" || echo \"❌ Jest tests failed!\""
  }
}

Now you can just run npm run test:silent (or yarn test:silent) whenever you want a quiet test run with straightforward feedback.

Why this works #

Jest doesn’t have a built-in flag to completely silence output while only showing a pass/fail message, but we can leverage shell redirection and exit codes to pull this off. All programs return an exit code: 0 means success, and any non-zero code indicates an error. We use this universal convention to trigger the appropriate message after silencing all Jest output.

内容的提问来源于stack exchange，提问作者ThomasReggi