autoprefixer/lib/hacks/background-size.js

Parse CSS and add vendor prefixes to CSS rules using values from the Can I Use website

let Declaration = require('../declaration')

class BackgroundSize extends Declaration {
  /**
   * Duplication parameter for -webkit- browsers
   */
  set(decl, prefix) {
    let value = decl.value.toLowerCase()
    if (
      prefix === '-webkit-' &&
      !value.includes(' ') &&
      value !== 'contain' &&
      value !== 'cover'
    ) {
      decl.value = decl.value + ' ' + decl.value
    }
    return super.set(decl, prefix)
  }
}

BackgroundSize.names = ['background-size']

module.exports = BackgroundSize