Description

Our team found a potential edge case while working on our Bootstrap fork.

When using the current version of color-mode.js:

  const setTheme = theme => {
    if (theme === 'auto' && window.matchMedia('(prefers-color-scheme: dark)').matches) {
      document.documentElement.setAttribute('data-bs-theme', 'dark')
    } else {
      document.documentElement.setAttribute('data-bs-theme', theme)
    }
  }

The results will be:

At this point you may have an edge case when your device is set to 'Light mode' and you use the 'Auto color mode' on the page because you will have to add more CSS to make something like:

@media (prefers-color-scheme: light) {
  [data-bs-theme="auto"] {
    // your code...
  }
}

Proposed patch:

  const setTheme = theme => {
- if (theme === 'auto' && window.matchMedia('(prefers-color-scheme: dark)').matches) {
-   document.documentElement.setAttribute('data-bs-theme', 'dark')
+ if (theme === 'auto') {
+   document.documentElement.setAttribute('data-bs-theme', (window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'))
  } else {

Then you will have:

And you don't need to add extra CSS everywhere.

Motivation & Context

Fix edge case when your device is set to 'Light mode' and you use the 'Auto color mode' on the page.

Type of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the contributing guidelines
• My code follows the code style of the project (using npm run lint)
• (na) My change introduces changes to the documentation
• (na) I have updated the documentation accordingly
• (na) I have added tests to cover my changes
• All new and existing tests passed

Live previews

• https://deploy-preview-39224--twbs-bootstrap.netlify.app/