工具 API

工具 API 是一个基于 Sass 的工具，用于生成工具类。

Bootstrap 工具是使用我们的工具 API 生成的，可用于通过 Sass 修改或扩展我们默认的工具类集。我们的工具 API 基于一系列 Sass 映射和函数，用于生成具有各种选项的类系列。如果你不熟悉 Sass 映射，请阅读 Sass 官方文档以开始使用。

¥Bootstrap utilities are generated with our utility API and can be used to modify or extend our default set of utility classes via Sass. Our utility API is based on a series of Sass maps and functions for generating families of classes with various options. If you’re unfamiliar with Sass maps, read up on the official Sass docs to get started.

$utilities 映射包含我们的所有工具，稍后会与你的自定义 $utilities 映射（如果存在）合并。工具映射包含工具组的键控列表，这些工具组接受以下选项：

¥The $utilities map contains all our utilities and is later merged with your custom $utilities map, if present. The utility map contains a keyed list of utility groups which accept the following options:

Option	Type	Default value	Description
`property`	Required	–	Name of the property, this can be a string or an array of strings (e.g., horizontal paddings or margins).
`values`	Required	–	List of values, or a map if you don’t want the class name to be the same as the value. If `null` is used as map key, `class` is not prepended to the class name.
`class`	Optional	null	Name of the generated class. If not provided and `property` is an array of strings, `class` will default to the first element of the `property` array. If not provided and `property` is a string, the `values` keys are used for the `class` names.
`css-var`	Optional	`false`	Boolean to generate CSS variables instead of CSS rules.
`css-variable-name`	Optional	null	Custom un-prefixed name for the CSS variable inside the ruleset.
`local-vars`	Optional	null	Map of local CSS variables to generate in addition to the CSS rules.
`state`	Optional	null	List of pseudo-class variants (e.g., `:hover` or `:focus`) to generate.
`responsive`	Optional	`false`	Boolean indicating if responsive classes should be generated.
`rfs`	Optional	`false`	Boolean to enable fluid rescaling with RFS.
`print`	Optional	`false`	Boolean indicating if print classes need to be generated.
`rtl`	Optional	`true`	Boolean indicating if utility should be kept in RTL.

API 解释

¥API explained

所有工具变量都添加到 _utilities.scss 样式表中的 $utilities 变量中。每组工具看起来都像这样：

¥All utility variables are added to the $utilities variable within our _utilities.scss stylesheet. Each group of utilities looks something like this:

$utilities: (
  "opacity": (
    property: opacity,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
);

其输出如下：

¥Which outputs the following:

.opacity-0 { opacity: 0; }
.opacity-25 { opacity: .25; }
.opacity-50 { opacity: .5; }
.opacity-75 { opacity: .75; }
.opacity-100 { opacity: 1; }

属性

¥Property

必须为任何工具设置所需的 property 键，并且它必须包含有效的 CSS 属性。该属性用于生成的工具的规则集中。当省略 class 键时，它也用作默认类名。考虑 text-decoration 工具：

¥The required property key must be set for any utility, and it must contain a valid CSS property. This property is used in the generated utility’s ruleset. When the class key is omitted, it also serves as the default class name. Consider the text-decoration utility:

$utilities: (
  "text-decoration": (
    property: text-decoration,
    values: none underline line-through
  )
);

输出：

¥Output:

.text-decoration-none { text-decoration: none !important; }
.text-decoration-underline { text-decoration: underline !important; }
.text-decoration-line-through { text-decoration: line-through !important; }

值

¥Values

使用 values 键指定应在生成的类名称和规则中使用指定 property 的哪些值。可以是列表或映射（在工具或 Sass 变量中设置）。

¥Use the values key to specify which values for the specified property should be used in the generated class names and rules. Can be a list or map (set in the utilities or in a Sass variable).

作为一个列表，就像 text-decoration 实用程序一样：

¥As a list, like with text-decoration utilities:

values: none underline line-through

作为映射，就像 opacity 实用程序一样：

¥As a map, like with opacity utilities:

values: (
  0: 0,
  25: .25,
  50: .5,
  75: .75,
  100: 1,
)

作为设置列表或映射的 Sass 变量，如我们的 position 实用程序中所示：

¥As a Sass variable that sets the list or map, as in our position utilities:

values: $position-values

类

¥Class

使用 class 选项更改编译的 CSS 中使用的类前缀。例如，从 .opacity-* 更改为 .o-*：

¥Use the class option to change the class prefix used in the compiled CSS. For example, to change from .opacity-* to .o-*:

$utilities: (
  "opacity": (
    property: opacity,
    class: o,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
);

输出：

¥Output:

.o-0 { opacity: 0 !important; }
.o-25 { opacity: .25 !important; }
.o-50 { opacity: .5 !important; }
.o-75 { opacity: .75 !important; }
.o-100 { opacity: 1 !important; }

如果是 class: null，则为每个 values 键生成类：

¥If class: null, generates classes for each of the values keys:

$utilities: (
  "visibility": (
    property: visibility,
    class: null,
    values: (
      visible: visible,
      invisible: hidden,
    )
  )
);

输出：

¥Output:

.visible { visibility: visible !important; }
.invisible { visibility: hidden !important; }

CSS 变量工具

¥CSS variable utilities

将 css-var 布尔选项设置为 true，API 将为给定选择器生成本地 CSS 变量，而不是通常的 property: value 规则。添加可选的 css-variable-name 以设置与类名称不同的 CSS 变量名称。

¥Set the css-var boolean option to true and the API will generate local CSS variables for the given selector instead of the usual property: value rules. Add an optional css-variable-name to set a different CSS variable name than the class name.

考虑一下我们的 .text-opacity-* 工具。如果我们添加 css-variable-name 选项，我们将获得自定义输出。

¥Consider our .text-opacity-* utilities. If we add the css-variable-name option, we’ll get a custom output.

$utilities: (
  "text-opacity": (
    css-var: true,
    css-variable-name: text-alpha,
    class: text-opacity,
    values: (
      25: .25,
      50: .5,
      75: .75,
      100: 1
    )
  ),
);

输出：

¥Output:

.text-opacity-25 { --bs-text-alpha: .25; }
.text-opacity-50 { --bs-text-alpha: .5; }
.text-opacity-75 { --bs-text-alpha: .75; }
.text-opacity-100 { --bs-text-alpha: 1; }

局部 CSS 变量

¥Local CSS variables

使用 local-vars 选项指定将在工具类的规则集中生成本地 CSS 变量的 Sass 映射。请注意，可能需要额外的工作才能在生成的 CSS 规则中使用这些本地 CSS 变量。例如，考虑我们的 .bg-* 工具：

¥Use the local-vars option to specify a Sass map that will generate local CSS variables within the utility class’s ruleset. Please note that it may require additional work to consume those local CSS variables in the generated CSS rules. For example, consider our .bg-* utilities:

$utilities: (
  "background-color": (
    property: background-color,
    class: bg,
    local-vars: (
      "bg-opacity": 1
    ),
    values: map-merge(
      $utilities-bg-colors,
      (
        "transparent": transparent
      )
    )
  )
);

输出：

¥Output:

.bg-primary {
  --bs-bg-opacity: 1;
  background-color: rgba(var(--bs-primary-rgb), var(--bs-bg-opacity)) !important;
}

状态

¥States

使用 state 选项生成伪类变体。示例伪类是 :hover 和 :focus。当提供状态列表时，将为该伪类创建类名。例如，要更改悬停时的不透明度，请添加 state: hover，你将在编译的 CSS 中获得 .opacity-hover:hover。

¥Use the state option to generate pseudo-class variations. Example pseudo-classes are :hover and :focus. When a list of states are provided, classnames are created for that pseudo-class. For example, to change opacity on hover, add state: hover and you’ll get .opacity-hover:hover in your compiled CSS.

需要多个伪类？使用空格分隔的状态列表：state: hover focus。

¥Need multiple pseudo-classes? Use a space-separated list of states: state: hover focus.

$utilities: (
  "opacity": (
    property: opacity,
    class: opacity,
    state: hover,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
);

输出：

¥Output:

.opacity-0-hover:hover { opacity: 0 !important; }
.opacity-25-hover:hover { opacity: .25 !important; }
.opacity-50-hover:hover { opacity: .5 !important; }
.opacity-75-hover:hover { opacity: .75 !important; }
.opacity-100-hover:hover { opacity: 1 !important; }

响应式

¥Responsive

添加 responsive 布尔值以跨所有断点生成响应实用程序（例如 .opacity-md-25）。

¥Add the responsive boolean to generate responsive utilities (e.g., .opacity-md-25) across all breakpoints.

$utilities: (
  "opacity": (
    property: opacity,
    responsive: true,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
);

输出：

¥Output:

.opacity-0 { opacity: 0 !important; }
.opacity-25 { opacity: .25 !important; }
.opacity-50 { opacity: .5 !important; }
.opacity-75 { opacity: .75 !important; }
.opacity-100 { opacity: 1 !important; }

@media (min-width: 576px) {
  .opacity-sm-0 { opacity: 0 !important; }
  .opacity-sm-25 { opacity: .25 !important; }
  .opacity-sm-50 { opacity: .5 !important; }
  .opacity-sm-75 { opacity: .75 !important; }
  .opacity-sm-100 { opacity: 1 !important; }
}

@media (min-width: 768px) {
  .opacity-md-0 { opacity: 0 !important; }
  .opacity-md-25 { opacity: .25 !important; }
  .opacity-md-50 { opacity: .5 !important; }
  .opacity-md-75 { opacity: .75 !important; }
  .opacity-md-100 { opacity: 1 !important; }
}

@media (min-width: 992px) {
  .opacity-lg-0 { opacity: 0 !important; }
  .opacity-lg-25 { opacity: .25 !important; }
  .opacity-lg-50 { opacity: .5 !important; }
  .opacity-lg-75 { opacity: .75 !important; }
  .opacity-lg-100 { opacity: 1 !important; }
}

@media (min-width: 1200px) {
  .opacity-xl-0 { opacity: 0 !important; }
  .opacity-xl-25 { opacity: .25 !important; }
  .opacity-xl-50 { opacity: .5 !important; }
  .opacity-xl-75 { opacity: .75 !important; }
  .opacity-xl-100 { opacity: 1 !important; }
}

@media (min-width: 1400px) {
  .opacity-xxl-0 { opacity: 0 !important; }
  .opacity-xxl-25 { opacity: .25 !important; }
  .opacity-xxl-50 { opacity: .5 !important; }
  .opacity-xxl-75 { opacity: .75 !important; }
  .opacity-xxl-100 { opacity: 1 !important; }
}

打印

¥Print

启用 print 选项还将生成用于打印的工具类，这些工具类仅在 @media print { ... } 媒体查询中应用。

¥Enabling the print option will also generate utility classes for print, which are only applied within the @media print { ... } media query.

$utilities: (
  "opacity": (
    property: opacity,
    print: true,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
);

输出：

¥Output:

.opacity-0 { opacity: 0 !important; }
.opacity-25 { opacity: .25 !important; }
.opacity-50 { opacity: .5 !important; }
.opacity-75 { opacity: .75 !important; }
.opacity-100 { opacity: 1 !important; }

@media print {
  .opacity-print-0 { opacity: 0 !important; }
  .opacity-print-25 { opacity: .25 !important; }
  .opacity-print-50 { opacity: .5 !important; }
  .opacity-print-75 { opacity: .75 !important; }
  .opacity-print-100 { opacity: 1 !important; }
}

重要性

¥Importance

API 生成的所有工具都包含 !important，以确保它们按预期重写组件和修饰符类。你可以使用 $enable-important-utilities 变量（默认为 true）全局切换此设置。

¥All utilities generated by the API include !important to ensure they override components and modifier classes as intended. You can toggle this setting globally with the $enable-important-utilities variable (defaults to true).

使用 API

¥Using the API

现在你已经熟悉了工具 API 的工作原理，接下来了解如何添加你自己的自定义类并修改我们的默认工具。

¥Now that you’re familiar with how the utilities API works, learn how to add your own custom classes and modify our default utilities.

覆盖工具

¥Override utilities

使用相同的密钥覆盖现有工具。例如，如果你想要其他响应式溢出工具类，你可以这样做：

¥Override existing utilities by using the same key. For example, if you want additional responsive overflow utility classes, you can do this:

$utilities: (
  "overflow": (
    responsive: true,
    property: overflow,
    values: visible hidden scroll auto,
  ),
);

添加工具

¥Add utilities

可以使用 map-merge 将新工具添加到默认 $utilities 映射中。确保首先导入我们所需的 Sass 文件和 _utilities.scss，然后使用 map-merge 添加其他工具。例如，以下是如何添加具有三个值的响应式 cursor 工具。

¥New utilities can be added to the default $utilities map with a map-merge. Make sure our required Sass files and _utilities.scss are imported first, then use the map-merge to add your additional utilities. For example, here’s how to add a responsive cursor utility with three values.

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

$utilities: map-merge(
  $utilities,
  (
    "cursor": (
      property: cursor,
      class: cursor,
      responsive: true,
      values: auto pointer grab,
    )
  )
);

@import "bootstrap/scss/utilities/api";

修改工具

¥Modify utilities

使用 map-get 和 map-merge 功能修改默认 $utilities 映射中的现有工具。在下面的示例中，我们向 width 工具添加一个附加值。从初始 map-merge 开始，然后指定要修改的工具。从那里，获取带有 map-get 的嵌套 "width" 映射以访问和修改工具的选项和值。

¥Modify existing utilities in the default $utilities map with map-get and map-merge functions. In the example below, we’re adding an additional value to the width utilities. Start with an initial map-merge and then specify which utility you want to modify. From there, fetch the nested "width" map with map-get to access and modify the utility’s options and values.

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

$utilities: map-merge(
  $utilities,
  (
    "width": map-merge(
      map-get($utilities, "width"),
      (
        values: map-merge(
          map-get(map-get($utilities, "width"), "values"),
          (10: 10%),
        ),
      ),
    ),
  )
);

@import "bootstrap/scss/utilities/api";

启用响应式

¥Enable responsive

你可以为当前默认情况下不响应的一组现有工具启用响应类。例如，要使 border 类响应：

¥You can enable responsive classes for an existing set of utilities that are not currently responsive by default. For example, to make the border classes responsive:

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

$utilities: map-merge(
  $utilities,
  (
    "border": map-merge(
      map-get($utilities, "border"),
      ( responsive: true ),
    ),
  )
);

@import "bootstrap/scss/utilities/api";

现在将为每个断点生成 .border 和 .border-0 的响应变体。你生成的 CSS 将如下所示：

¥This will now generate responsive variations of .border and .border-0 for each breakpoint. Your generated CSS will look like this:

.border { ... }
.border-0 { ... }

@media (min-width: 576px) {
  .border-sm { ... }
  .border-sm-0 { ... }
}

@media (min-width: 768px) {
  .border-md { ... }
  .border-md-0 { ... }
}

@media (min-width: 992px) {
  .border-lg { ... }
  .border-lg-0 { ... }
}

@media (min-width: 1200px) {
  .border-xl { ... }
  .border-xl-0 { ... }
}

@media (min-width: 1400px) {
  .border-xxl { ... }
  .border-xxl-0 { ... }
}

重命名工具

¥Rename utilities

缺少 v4 工具，或者习惯了其他命名约定？工具 API 可用于覆盖给定工具生成的 class，例如，将 .ms-* 工具重命名为旧的 .ml-*：

¥Missing v4 utilities, or used to another naming convention? The utilities API can be used to override the resulting class of a given utility—for example, to rename .ms-* utilities to oldish .ml-*:

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

$utilities: map-merge(
  $utilities,
  (
    "margin-start": map-merge(
      map-get($utilities, "margin-start"),
      ( class: ml ),
    ),
  )
);

@import "bootstrap/scss/utilities/api";

删除工具

¥Remove utilities

使用 map-remove() Sass 函数删除任何默认工具。

¥Remove any of the default utilities with the map-remove() Sass function.

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

// Remove multiple utilities with a comma-separated list
$utilities: map-remove($utilities, "width", "float");

@import "bootstrap/scss/utilities/api";

你还可以使用 map-merge() Sass 函数并将组密钥设置为 null 来删除该工具。

¥You can also use the map-merge() Sass function and set the group key to null to remove the utility.

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

$utilities: map-merge(
  $utilities,
  (
    "width": null
  )
);

@import "bootstrap/scss/utilities/api";

添加、删除、修改

¥Add, remove, modify

你可以使用 map-merge() Sass 函数一次性添加、删除和修改许多工具。以下是如何将前面的示例合并到一张更大的映射中。

¥You can add, remove, and modify many utilities all at once with the map-merge() Sass function. Here’s how you can combine the previous examples into one larger map.

@import "bootstrap/scss/functions";
@import "bootstrap/scss/variables";
@import "bootstrap/scss/variables-dark";
@import "bootstrap/scss/maps";
@import "bootstrap/scss/mixins";
@import "bootstrap/scss/utilities";

$utilities: map-merge(
  $utilities,
  (
    // Remove the `width` utility
    "width": null,
    // Make an existing utility responsive
    "border": map-merge(
      map-get($utilities, "border"),
      ( responsive: true ),
    ),
    // Add new utilities
    "cursor": (
      property: cursor,
      class: cursor,
      responsive: true,
      values: auto pointer grab,
    )
  )
);

@import "bootstrap/scss/utilities/api";

删除 RTL 中的工具

¥Remove utility in RTL

某些边缘情况会导致 RTL 样式困难，例如阿拉伯语中的换行符。因此，可以通过将 rtl 选项设置为 false 从 RTL 输出中删除工具：

¥Some edge cases make RTL styling difficult, such as line breaks in Arabic. Thus utilities can be dropped from RTL output by setting the rtl option to false:

$utilities: (
  "word-wrap": (
    property: word-wrap word-break,
    class: text,
    values: (break: break-word),
    rtl: false
  ),
);

输出：

¥Output:

/* rtl:begin:remove */
.text-break {
  word-wrap: break-word !important;
  word-break: break-word !important;
}
/* rtl:end:remove */

由于 RTLCSS remove 控制指令，这不会在 RTL 中输出任何内容。

¥This doesn’t output anything in RTL, thanks to the RTLCSS remove control directive.