重大变更：meta.feature-exists()
meta.feature-exists() 函数很长时间没有添加新功能，现在已被弃用。用户应使用其他方法来确定新功能是否可用。
历史上，Sass 使用 meta.feature-exists() 函数（也可作为全局 feature-exists() 函数）允许作者在编译样式表时检测各种新语言功能是否可用。然而，随着时间的推移，事实证明绝大多数新的 Sass 功能要么可以用更直接的方式检测，要么根本不值得检测。
这个函数现在已被弃用，并将在 Dart Sass 2.0.0 中被移除。由于 Dart Sass 现在是唯一官方支持的 Sass 实现，并且所有版本的 Dart Sass 都支持 meta.feature-exists() 支持的所有功能，因此可以安全地删除所有现有的使用。
许多新功能可以使用 meta.function-exists()、meta.mixin-exists() 或 [meta.global-variable-exists()] 来检测。其他功能可以使用表达式级语法检测，例如使用 calc(1) == 1 来确定当前版本的 Sass 是否支持一级计算。
过渡期过渡期 permalink
- Dart Sass
- since 1.78.0
- LibSass
- ✗
- Ruby Sass
- ✗
首先，我们将为所有 feature-exists 的使用情况发出弃用警告。
在 Dart Sass 2.0.0 中，meta.feature-exists() 将不再存在。尝试调用它将引发错误，尝试调用全局 feature-exists() 函数将被视为普通的 CSS 函数调用。
Can I Silence the Warnings?Can I Silence the Warnings? permalink
Sass provides a powerful suite of options for managing which deprecation warnings you see and when.
Terse and Verbose ModeTerse and Verbose Mode permalink
By default, Sass runs in terse mode, where it will only print each type of deprecation warning five times before it silences additional warnings. This helps ensure that users know when they need to be aware of an upcoming breaking change without creating an overwhelming amount of console noise.
If you run Sass in verbose mode instead, it will print every deprecation
warning it encounters. This can be useful for tracking the remaining work to be
done when fixing deprecations. You can enable verbose mode using
the --verbose flag on the command line, or
the verbose option in the JavaScript API.
⚠️ Heads up!
When running from the JS API, Sass doesn’t share any information across
compilations, so by default it’ll print five warnings for each stylesheet
that’s compiled. However, you can fix this by writing (or asking the author of
your favorite framework’s Sass plugin to write) a custom Logger that only
prints five errors per deprecation and can be shared across multiple compilations.
Silencing Deprecations in DependenciesSilencing Deprecations in Dependencies permalink
Sometimes, your dependencies have deprecation warnings that you can’t do
anything about. You can silence deprecation warnings from dependencies while
still printing them for your app using
the --quiet-deps flag on the command line, or
the quietDeps option in the JavaScript API.
For the purposes of this flag, a "dependency" is any stylesheet that’s not just a series of relative loads from the entrypoint stylesheet. This means anything that comes from a load path, and most stylesheets loaded through custom importers.
Silencing Specific DeprecationsSilencing Specific Deprecations permalink
If you know that one particular deprecation isn’t a problem for you, you can
silence warnings for that specific deprecation using
the --silence-deprecation flag on the command line, or
the silenceDeprecations option in the JavaScript API.