無効化したい機能もあるでしょう。
https://github.com/MoOx/postcss-cssnext/blob/master/src/features.js
Feature
| Property | Require | Npm |
|---|---|---|
| customProperties | require("postcss-custom-properties")(options) | https://npmjs.com/package/postcss-custom-properties |
| applyRule | require("postcss-apply")(options) | https://npmjs.com/package/postcss-apply |
| calc | require("postcss-calc")(options) | https://npmjs.com/package/postcss-calc |
| nesting | require("postcss-nesting")(options) | https://npmjs.com/package/postcss-nesting |
| customMedia | require("postcss-custom-media")(options) | https://npmjs.com/package/postcss-custom-media |
| mediaQueriesRange | require("postcss-media-minmax")(options) | https://npmjs.com/package/postcss-media-minmax |
| customSelectors | require("postcss-custom-selectors")(options) | https://npmjs.com/package/postcss-custom-selectors |
| attributeCaseInsensitive | require("postcss-attribute-case-insensitive")(options) | https://npmjs.com/package/postcss-attribute-case-insensitive |
| colorRebeccapurple | require("postcss-color-rebeccapurple")(options) | https://npmjs.com/package/postcss-color-rebeccapurple |
| colorHwb | require("postcss-color-hwb")(options) | https://npmjs.com/package/postcss-color-hwb |
| colorGray | require("postcss-color-gray")(options) | https://npmjs.com/package/postcss-color-gray |
| colorHexAlpha | require("postcss-color-hex-alpha")(options) | https://npmjs.com/package/postcss-color-hex-alpha |
| colorFunction | require("postcss-color-function")(options) | https://npmjs.com/package/postcss-color-function |
| fontVariant | require("postcss-font-variant")(options) | https://npmjs.com/package/postcss-font-variant |
| filter | require("pleeease-filters")(options) | https://npmjs.com/package/pleeease-filters |
| initial | require("postcss-initial")(options) | https://npmjs.com/package/postcss-initial |
| rem | require("pixrem")(options) | https://npmjs.com/package/pixrem |
| pseudoElements | require("postcss-pseudoelements")(options) | https://npmjs.com/package/postcss-pseudoelements |
| pseudoClassMatches | require("postcss-selector-matches")(options) | https://npmjs.com/package/postcss-selector-matches |
| pseudoClassNot | require("postcss-selector-not")(options) | https://npmjs.com/package/postcss-selector-not |
| pseudoClassAnyLink | require("postcss-pseudo-class-any-link")(options) | https://npmjs.com/package/postcss-pseudo-class-any-link |
| colorRgba | require("postcss-color-rgba-fallback")(options) | https://npmjs.com/package/postcss-color-rgba-fallback |
| overflowWrap | require("postcss-replace-overflow-wrap")(options) | https://www.npmjs.com/package/postcss-replace-overflow-wrap |
| autoprefixer | require("autoprefixer")(options) | https://npmjs.com/package/autoprefixer |
js
// 無効化サンプル
var output = cssnext(input, {
features: {
calc: false,
rem: false
}
})