Migrating to Stylable v3

This guide is intended to help migrate Stylable version 1 to Stylable version 2 or 3. It is mainly geared towards Stylable integration in React projects.

Suggested steps of migration

Follow these steps for a smooth transition. Each step is explained in more detail below.

  1. Update dependencies
  2. Update global typings
  3. Update .st.css file imports
  4. Update usage in React components
  5. Update tests

Update dependencies

Ensure you have v3 Stylable dependencies available. You may need to update your package.json or ensure that other dependencies bring you v3 Stylable:

Note: all Stylable packages in v3 are scoped under @stylable namespace. if you have dependency like stylable (without namespace), it is a different one and should be changed to scoped version.

Update global typings

If TypeScript is used in the project, we recommend updating the global typings (usually globals.d.ts) with an .st.css module declaration:

declare module '*.st.css' {
  const stylesheet: import('@stylable/runtime').RuntimeStylesheet;
  export = stylesheet;

This way the TypeScript compiler will help refactor most of the required changes and provide typings for other Stylable use cases.

Update .st.css file imports

Prior to v2 all .st.css files would export a default style function. In v2 this has changed: .st.css files now export a named object.

List of all exported keys:

import {
  st, // alias to `style`
} from './style.st.css';

This means that all imports of .st.css files have to be changed, for example:

-import style from './Component.st.css';
+import { st, classes, /* ... */ } from './Component.st.css';

However, most often { st, classes } is enough:

import { st, classes } from './Component.st.css';

Note: .st.css files export a style function and an alias to it - st. It is recommended to use st in order to avoid name clashing with other variables (for example, some other inline style).

CSS custom properties

Stylable now localizes CSS Custom Properties. This means that any usage of Custom Proprties (e.g. --prop) should now be incorparated in the component code.

See the docs about CSS custom properties for usage examples.

Update usage in React components

Once .st.css imports are updated, React components should be updated too:

-<div {...style('root', states, props)} /> />
+<div className={st(classes.root, states, props.className)} />

There are subtle but very important nuances in this change.

  1. Stylable v1 used spread pattern. It would take the output of style('root', states, this.props) function and spread it on component.

    This way one or more props would be applied to the component. Thus, code that looks like this:

      <div {...style('root', {}, { className: 'additional-class', 'data-hook': 'test' })} />

    once evaluated, would behave like this:

        className="root additional-class"

    Stylable v2 and v3 usage is like so:

      className={st(classes.root, states, this.props.className)}

    There is no props spreading anymore and Stylable requires only className to be used.

    However, if you were relying on the props spread pattern, in v2 and v3 you might find some props missing.

    Therefore, with Stylable v3 it is up to you to apply any additional props:

      <div className={st(classes.root, states, 'additional-class')} 
           hello="world" />
  2. Stylable v1 style() would accept unscoped css class name as a string
    This is no longer acceptable in Stylable v2 or v3, for example:

     -<div {...style('root', state, { className: 'additional-class-name' })} />
     +<div className={style(classes.root, 'additional-class-name')} />

    note that classes.root comes from .st.css, which is the correct way to import class names.

    Similar scoping is applied to css variables too, imported from vars

Note: find more details and examples in our Runtime and React integration guides.

Update tests

If you were using @stylable/dom-test-kit in Stylable v1, it’s usage is slightly different in v2 and v3:

import { StylableDOMUtil } from '@Stylable/dom-test-kit';
-import style from './Component.st.css';
+import * as styleSheet from './Component.st.css';

-const StylableDOMUtil = new StylableDOMUtil(style);
+const StylableDOMUtil = new StylableDOMUtil(styleSheet);

Stylable v2 and v3 StylableDOMUtil expects to receive an argument which is the whole stylesheet exported from a .st.css file

Prior to v2 it was only one thing - the style function.