Utility API
The utility API is a Sass-based tool to generate utility classes.
🤖 Looking for the LLM-optimized version?View llm.md
CoreUI for 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 theofficial Sass docs to get started.
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. Ifnull is used as map key,class is not prepended to the class name. |
class | Optional | null | Name of the generated class. If not provided andproperty is an array of strings,class will default to the first element of theproperty array. If not provided andproperty is a string, thevalues keys are used for theclass 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 enablefluid 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 explained
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,)));Which outputs the following:
.opacity-0{opacity:0;}.opacity-25{opacity:.25;}.opacity-50{opacity:.5;}.opacity-75{opacity:.75;}.opacity-100{opacity:1;}Property
The requiredproperty 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 theclass key is omitted, it also serves as the default class name. Consider thetext-decoration utility:
$utilities:("text-decoration":(property:text-decoration,values:noneunderlineline-through));Output:
.text-decoration-none{text-decoration:none!important;}.text-decoration-underline{text-decoration:underline!important;}.text-decoration-line-through{text-decoration:line-through!important;}Values
Use thevalues key to specify which values for the specifiedproperty should be used in the generated class names and rules. Can be a list or map (set in the utilities or in a Sass variable).
As a list, like withtext-decoration utilities:
values:noneunderlineline-throughAs a map, like withopacity utilities:
values:(0:0,25:.25,50:.5,75:.75,100:1,)As a Sass variable that sets the list or map, as in ourposition utilities:
values:$position-valuesClass
Use theclass 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,)));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;}Ifclass: null, generates classes for each of thevalues keys:
$utilities:("visibility":(property:visibility,class:null,values:(visible:visible,invisible:hidden,)));Output:
.visible{visibility:visible!important;}.invisible{visibility:hidden!important;}CSS variable utilities
Set thecss-var boolean option totrue and the API will generate local CSS variables for the given selector instead of the usualproperty: value rules. Add an optionalcss-variable-name to set a different CSS variable name than the class name.
Consider our.text-opacity-* utilities. If we add thecss-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)),);Output:
.text-opacity-25{--cui-text-opacity:.25;}.text-opacity-50{--cui-text-opacity:.5;}.text-opacity-75{--cui-text-opacity:.75;}.text-opacity-100{--cui-text-opacity:1;}Local CSS variables
Use thelocal-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))));Output:
.bg-primary{--cui-bg-opacity:1;background-color:rgba(var(--cui-primary-rgb),var(--cui-bg-opacity))!important;}States
Use thestate 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, addstate: hover and you’ll get.opacity-hover:hover in your compiled CSS.
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,)));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;}Responsive
Add theresponsive boolean to generate responsive utilities (e.g.,.opacity-md-25) acrossall breakpoints.
$utilities:("opacity":(property:opacity,responsive:true,values:(0:0,25:.25,50:.5,75:.75,100:1,)));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;}}Enabling theprint option willalso generate utility classes for print, which are only applied within the@media print { ... } media query.
$utilities:("opacity":(property:opacity,print:true,values:(0:0,25:.25,50:.5,75:.75,100:1,)));Output:
.opacity-0{opacity:0!important;}.opacity-25{opacity:.25!important;}.opacity-50{opacity:.5!important;}.opacity-75{opacity:.75!important;}.opacity-100{opacity:1!important;}@mediaprint{.opacity-print-0{opacity:0!important;}.opacity-print-25{opacity:.25!important;}.opacity-print-50{opacity:.5!important;}.opacity-print-75{opacity:.75!important;}.opacity-print-100{opacity:1!important;}}Importance
All utilities generated by the API include!important to ensure they override components and modifier classes as intended. You can toggle this setting globally with the$enable-important-utilities variable (defaults totrue).
Using the API
Now that you’re familiar with how the utilities API works, learn how to add your own custom classes and modify our default utilities.
Override utilities
Override existing utilities by using the same key. For example, if you want additional responsive overflow utility classes, you can do this:
$utilities:("overflow":(responsive:true,property:overflow,values:visiblehiddenscrollauto,),);Add utilities
New utilities can be added to the default$utilities map with amap-merge. Make sure our required Sass files and_utilities.scss are imported first, then use themap-merge to add your additional utilities. For example, here’s how to add a responsivecursor utility with three values.
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";$utilities:map-merge($utilities,("cursor":(property:cursor,class:cursor,responsive:true,values:autopointergrab,)));@import"@coreui/coreui/scss/utilities/api";Modify utilities
Modify existing utilities in the default$utilities map withmap-get andmap-merge functions. In the example below, we’re adding an additional value to thewidth utilities. Start with an initialmap-merge and then specify which utility you want to modify. From there, fetch the nested"width" map withmap-get to access and modify the utility’s options and values.
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";$utilities:map-merge($utilities,("width":map-merge(map-get($utilities,"width"),(values:map-merge(map-get(map-get($utilities,"width"),"values"),(10:10%),),),),));@import"@coreui/coreui/scss/utilities/api";Enable responsive
You can enable responsive classes for an existing set of utilities that are not currently responsive by default. For example, to make theborder classes responsive:
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";$utilities:map-merge($utilities,("border":map-merge(map-get($utilities,"border"),(responsive:true),),));@import"@coreui/coreui/scss/utilities/api";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{...}}Rename utilities
Missing v4 utilities, or used to another naming convention? The utilities API can be used to override the resultingclass of a given utility—for example, to rename.ms-* utilities to oldish.ml-*:
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";$utilities:map-merge($utilities,("margin-start":map-merge(map-get($utilities,"margin-start"),(class:ml),),));@import"@coreui/coreui/scss/utilities/api";Remove utilities
Remove any of the default utilities with themap-remove() Sass function.
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";// Remove multiple utilities with a comma-separated list$utilities:map-remove($utilities,"width","float");@import"@coreui/coreui/scss/utilities/api";You can also use themap-merge() Sass function and set the group key tonull to remove the utility.
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";$utilities:map-merge($utilities,("width":null));@import"@coreui/coreui/scss/utilities/api";Add, remove, modify
You can add, remove, and modify many utilities all at once with themap-merge() Sass function. Here’s how you can combine the previous examples into one larger map.
@import"@coreui/coreui/scss/functions";@import"@coreui/coreui/scss/variables";@import"@coreui/coreui/scss/maps";@import"@coreui/coreui/scss/mixins";@import"@coreui/coreui/scss/utilities";$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:autopointergrab,)));@import"@coreui/coreui/scss/utilities/api";