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    react-native-postcss-transformer NPM version Downloads per month contributions welcome

    Use PostCSS to style your React Native apps.

    Behind the scenes the PostCSS files are transformed to react native style objects (look at the examples).

    This transformer can be used together with React Native CSS modules.

    How does it work?

    Your App.css file might look like this (using postcss-css-variables plugin):

    :root {
      --blue-color: blue;
    .myClass {
      color: var(--blue-color);
    .myOtherClass {
      color: red;
    .my-dashed-class {
      color: green;

    When you import your stylesheet:

    import styles from "./App.css";

    Your imported styles will look like this:

    var styles = {
      myClass: {
        color: "blue"
      myOtherClass: {
        color: "red"
      "my-dashed-class": {
        color: "green"

    You can then use that style object with an element:

    Plain React Native:

    <MyElement style={styles.myClass} />
    <MyElement style={styles["my-dashed-class"]} />

    React Native CSS modules using className property:

    <MyElement className={styles.myClass} />
    <MyElement className={styles["my-dashed-class"]} />

    React Native CSS modules using styleName property:

    <MyElement styleName="myClass my-dashed-class" />

    Installation and configuration

    Step 1: Install

    yarn add --dev react-native-postcss-transformer postcss

    Step 2: Add your PostCSS config and install your PostCSS plugins

    Add your PostCSS configuration to one of the supported config formats, e.g. package.json, .postcssrc, postcss.config.js, etc.

    Step 3: Configure the react native packager

    For React Native v0.57 or newer / Expo SDK v31.0.0 or newer

    Add this to metro.config.js in your project's root (create the file if it does not exist already):

    const { getDefaultConfig } = require("metro-config");
    module.exports = (async () => {
      const {
        resolver: { sourceExts } 
      } = await getDefaultConfig();
      return {
        transformer: {
          babelTransformerPath: require.resolve("./postcss-transformer.js")
        resolver: {
          sourceExts: [...sourceExts, "css", "pcss"]

    If you are using Expo, you also need to add this to app.json:

      "expo": {
        "packagerOpts": {
          "config": "metro.config.js"

    For React Native v0.56 or older

    If you are using React Native without Expo, add this to rn-cli.config.js in your project's root (create the file if you don't have one already):

    module.exports = {
      getTransformModulePath() {
        return require.resolve("./postcss-transformer.js");
      getSourceExts() {
        return ["js", "jsx", "css", "pcss"]; // <-- Add other extensions if needed.

    For Expo SDK v30.0.0 or older

    If you are using Expo, instead of adding the rn-cli.config.js file, you need to add this to app.json:

      "expo": {
        "packagerOpts": {
          "sourceExts": ["js", "jsx", "css", "pcss"],
          "transformer": "./postcss-transformer.js"

    Step 4: Add transformer file

    Create postcss-transformer.js file to your project's root and specify supported extensions:

    // For React Native version 0.59 or later
    var upstreamTransformer = require("metro-react-native-babel-transformer");
    // For React Native version 0.56-0.58
    // var upstreamTransformer = require("metro/src/reactNativeTransformer");
    // For React Native version 0.52-0.55
    // var upstreamTransformer = require("metro/src/transformer");
    // For React Native version 0.47-0.51
    // var upstreamTransformer = require("metro-bundler/src/transformer");
    // For React Native version 0.46
    // var upstreamTransformer = require("metro-bundler/build/transformer");
    var postcssTransformer = require("react-native-postcss-transformer");
    var postCSSExtensions = ["css", "pcss"]; // <-- Add other extensions if needed.
    module.exports.transform = function({ src, filename, options }) {
      if (postCSSExtensions.some(ext => filename.endsWith("." + ext))) {
        return postcssTransformer.transform({ src, filename, options });
      return upstreamTransformer.transform({ src, filename, options });


    This library has the following Node.js modules as dependencies:





    npm i react-native-postcss-transformer

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    • kristerkari