Runtime

Imported Stylable stylesheets contain minimal runtime code to help define the structure and state of the component.

/* style.st.css */
.root {
    -st-states: selected;
}
.label {}
.icon {}
/* index.jsx - stylesheet's runtime api */
import { 
    style,    // runtime utility function 
    classes,  // class names mapping
    vars,     // css variables mapping
    stVars,   // stylable build-time variable values
    cssStates // utility function for setting stylable states
}  from "style.st.css";

Manual mapping

CSS class names, defined in the stylesheet, are exposed on the imported classes reference and mapped to their runtime target value. The expected class name is then used as an element class name in the structure.

classes.root  // "style__root"
classes.label // "style__label"
classes.icon  // "style__icon"

Note
The root class is available even when it is not defined in the stylesheet.

Custom state mapping

Custom states, which can be targeted from the style, are generated using the cssStates function. The function accepts a map of local state names and generates string with concatenated class names used to mark the element state.

/* { 'data-style-selected':true } */
cssStates({ selected:true })
/* { 'data-style-unknownstate':true } */
cssStates({ unknownState:true })

/* { } */
cssStates({ selected:false }) // no states

/* { 'data-style-a':true, 'data-style-b':true } */
cssStates({ a:true, b:true }) // multiple

Generate element attributes

The minimal runtime provides a function to help with component definition.
Calling the function returns an object describing the attributes of a node in the component view.

Element name

The first argument represents the scoped name of the element, and passes through the received class name.

/* 'style__root'  */
style(classes.root) 
/* 'style__label' */
style(classes.label) 

// multiple markings
style(classes.label, classes.icon) 
/* 'style__label style__icon' */

// string pass-through
style('root') 
/* 'root' */

Note
Stylable no longer performs auto-scoping for classes, and strings are passed as-is. Use the classes mapping object to resolve to the scoped class name.

Custom states

The second argument represents the custom state (or another class), and returns a class to represent every custom state on the element.

/* 'style__root style--selected' */
style(classes.root, { selected:true })
/* 'style__label style--searched' */
style(classes.label, { searched:true })

Merge props

The third argument (and any arguments after) can be used for any additional classes that need to be applied to the element. In a component root node, it is recommended to pass along the className prop received through your parent component as props.

// this.props.className = 'app__root app--selected'
/*  'style__root app__root app--selected' */
style(classes.root, this.props.className)

/*  'style__root label icon' */
style(classes.root, 'label', 'icon') // label and icon are global (un-scoped)

/*  'style__root style--selected' */
style(classes.root, 'style--selected')