True rules isolation through automatic properties reset

Some of the CSS properties are inheritable. It means that these properties apply to the child nodes from parent nodes. See this article for more details.

Due to this reason styles in reusable UI components can be broken if all inheritable properties were not defined explicitly for each element. It can cost You extra efforts to build strong isolation in a component.

This plugin protects styles from inheritance. It automatically creates a reset rule and applies to every user's rule.

Optionally you can also reset non-inherited properties, which would lead to even stronger isolation, as a protection against "greedy" selectors.

Make sure you read how to use plugins in general.

Usage example

const styles = {
  // All atRules will be ignored in reset.
  '@font-face': {
    fontFamily: 'MyHelvetica',
    src: 'local("Helvetica")',
  },
  title: {
    fontSize: 20,
    background: '#f00',
  },
  link: {
    fontSize: 12,
  },
  article: {
    isolate: false, // This rule will be ignored in reset.
    margin: '20px 10px 30px'
  }
}

Option isolate

Option isolate can be a boolean or a string. The default value is true, but you can override it in 3 different layers. For string value see Isolation by convention.

1. Globally for all StyleSheets:

   jss.use(isolate({
     isolate: false
   }))
   
   const styles = {
     // Isolated.
     button: {
       isolate: true,
       color: 'red'
     },
     // Not isolated.
     a: {
       color: 'green'
     }
   }

2. For a specific StyleSheet:

   const styles = {
     // Isolated.
     root: {
       isolate: true,
       color: 'red'
     },
     // Not isolated.
     a: {
       color: 'green'
     }
   }
   
   jss.createStyleSheet(styles, {isolate: false})

3. For a specific Rule:

const styles = {
  button: {
    isolate: false,
    color: 'red'
  }
}

Isolation by convention

You can assign any string to the isolate option. It will be used to match a rule name to isolate. All other rules will remain unisolated.

jss.use(isolate({
  // Will match rule names `root` in all StyleSheets.
  isolate: 'root'
}))

const styles = {
  // Isolated.
  root: {
    color: 'red'
  },
  // Not isolated.
  a: {
    color: 'green'
  }
}

Option reset

Default value for reset option is inherited.

If you want to reset some properties additionally to inherited once, you can pass a map of props-values. For e.g. you can set box-sizing to be border-box by default for every isolated rule without messing around with greedy selectors like this: * {box-sizing: border-box}.

jss.use(isolate({
  reset: {
    boxSizing: 'border-box'
  }
}))

If you want to reset all properties, not just inherited, use {reset: 'all'}.

jss.use(isolate({
  reset: 'all'
}))

If you want to reset all properties and extend the reset with your props:

jss.use(isolate({
  reset: ['all', {
    boxSizing: 'border-box'
  }]
}))

Demo

Simple

Reseted properties

Here are all inherited and all non-inherited properties we reset.

Issues

File a bug against cssinjs/jss prefixed with [jss-isolate].

Run tests

npm i
npm run test

License

MIT