Birthdate with default values return age less than 18

[mumumilk]

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Describe the bug

I was running into flaky tests in my application, and narrowed it down to faker's date.birthdate method.

According to the docs:

The options to use to generate the birthdate. If no options are set, an age between 18 and 80 (inclusive) is generated.

But there are times that an age less than 18 years old is generated. This does not happen every time, but I was able to get a specific seed and refDate to reproduce the issue.

Minimal reproduction code

https://stackblitz.com/edit/vitest-dev-vitest-md9oj6?file=test%2Fsuite.test.ts

Additional Context

No response

Environment Info

System:
    OS: macOS 13.0
    CPU: (8) arm64 Apple M2
    Memory: 65.42 MB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 16.20.2 - ~/.nvm/versions/node/v16.20.2/bin/node
    npm: 8.19.4 - ~/.nvm/versions/node/v16.20.2/bin/npm
    pnpm: 8.6.1 - ~/Library/pnpm/pnpm
    bun: 1.0.0 - ~/.bun/bin/bun
  Browsers:
    Chrome: 119.0.6045.123
    Edge: 119.0.2151.46
  npmPackages:
    @faker-js/faker: ^8.2.0 => 8.2.0

Which module system do you use?

• CJS
• ESM

Used Package Manager

npm

[ST-DDT]

I can confirm the bug.