budibase/packages/standard-components/src/cssVars.js

// https://github.com/kaisermann/svelte-css-vars

export default (node, props) => {
  Object.entries(props).forEach(([key, value]) => {
    node.style.setProperty(`--${key}`, value)
  })

  return {
    update(new_props) {
      Object.entries(new_props).forEach(([key, value]) => {
        node.style.setProperty(`--${key}`, value)
        delete props[key]
      })

      Object.keys(props).forEach(name => node.style.removeProperty(`--${name}`))
      props = new_props
    },
  }
}