Method remove

lib/processor.js:610–694

* Remove unnecessary pefixes

(css, result)

   * Remove unnecessary pefixes
   */
  remove(css, result) {
    // At-rules
    let resolution = this.prefixes.remove['@resolution']

    css.walkAtRules((rule, i) => {
      if (this.prefixes.remove[`@${rule.name}`]) {
        if (!this.disabled(rule, result)) {
          rule.parent.removeChild(i)
        }
      } else if (
        rule.name === 'media' &&
        rule.params.includes('-resolution') &&
        resolution
      ) {
        resolution.clean(rule)
      }
    })

    // Selectors
    css.walkRules((rule, i) => {
      if (this.disabled(rule, result)) return

      for (let checker of this.prefixes.remove.selectors) {
        if (checker.check(rule)) {
          rule.parent.removeChild(i)
          return
        }
      }
    })

    return css.walkDecls((decl, i) => {
      if (this.disabled(decl, result)) return

      let rule = decl.parent
      let unprefixed = this.prefixes.unprefixed(decl.prop)

      // Transition
      if (decl.prop === 'transition' || decl.prop === 'transition-property') {
        this.prefixes.transition.remove(decl)
      }

      // Properties
      if (
        this.prefixes.remove[decl.prop] &&
        this.prefixes.remove[decl.prop].remove
      ) {
        let notHack = this.prefixes.group(decl).down(other => {
          return this.prefixes.normalize(other.prop) === unprefixed
        })

        if (unprefixed === 'flex-flow') {
          notHack = true
        }

        if (decl.prop === '-webkit-box-orient') {
          let hacks = { 'flex-direction': true, 'flex-flow': true }
          if (!decl.parent.some(j => hacks[j.prop])) return
        }