Can't import CSS/SCSS modules. TypeScript says "Cannot Find Module"

I'm trying to import a theme from a CSS module but TypeScript gives me a "Cannot Find Module" error and the theme isn't applied on runtime. I think there's something wrong with my Webpack config but I'm not sure where the problem is.

I'm using the following tools:

"typescript": "^2.0.3"
"webpack": "2.1.0-beta.25"
"webpack-dev-server": "^2.1.0-beta.9"
"react": "^15.4.0-rc.4"
"react-toolbox": "^1.2.3"
"node-sass": "^3.10.1"
"style-loader": "^0.13.1"
"css-loader": "^0.25.0"
"sass-loader": "^4.0.2"
"sass-lint": "^1.9.1"
"sasslint-webpack-plugin": "^1.0.4"

Here is my webpack.config.js

var path = require('path');
var webpack = require('webpack');
var sassLintPlugin = require('sasslint-webpack-plugin');

module.exports = {
  entry: [
    'webpack-dev-server/client?http://localhost:8080',
    'webpack/hot/dev-server',
    './src/index.tsx',
  ],
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: 'http://localhost:8080/',
    filename: 'dist/bundle.js',
  },
  devtool: 'source-map',
  resolve: {
    extensions: ['.webpack.js', '.web.js', '.ts', '.tsx', '.js'],
  },
  module: {
    rules: [{
      test: /\.js$/,
      loader: 'source-map-loader',
      exclude: /node_modules/,
      enforce: 'pre',
    }, {
      test: /\.tsx?$/,
      loader: 'tslint-loader',
      exclude: /node_modules/,
      enforce: 'pre',
    }, {
      test: /\.tsx?$/,
      loaders: [
        'react-hot-loader/webpack',
        'awesome-typescript-loader',
      ],
      exclude: /node_modules/,
    }, {
      test: /\.scss$/,
      loaders: ['style', 'css', 'sass']
    }, {
      test: /\.css$/,
      loaders: ['style', 'css']
    }],
  },
  externals: {
    'react': 'React',
    'react-dom': 'ReactDOM'
  },
  plugins: [
    new sassLintPlugin({
      glob: 'src/**/*.s?(a|c)ss',
      ignoreFiles: ['src/normalize.scss'],
      failOnWarning: false, // Do it.
    }),
    new webpack.HotModuleReplacementPlugin(),
  ],
  devServer: {
    contentBase: './'
  },
};

and my App.tsx where I'm trying to import:

import * as React from 'react';

import { AppBar } from 'react-toolbox';
import appBarTheme from 'react-toolbox/components/app_bar/theme.scss'
// local ./theme.scss stylesheets aren't found either 

interface IAppStateProps {
  // No props yet
}

interface IAppDispatchProps {
  // No state yet
}

class App extends React.Component<IAppStateProps & IAppDispatchProps, any> {

  constructor(props: IAppStateProps & IAppDispatchProps) {
    super(props);
  }

  public render() {
    return (

        <div className='wrapper'>
          <AppBar title='My App Bar' theme={appBarTheme}>
          </AppBar>
        </div>

    );
  }
}

export default App;

What else is required to enable typesafe stylesheet module importing?

TypeScript does not know that there are files other than .tsor .tsx so it will throw an error if an import has an unknown file suffix.

If you have a webpack config that allows you to import other types of files, you have to tell the TypeScript compiler that these files exist. To do so add a declaration file in which you declare modules with fitting names.

The content of the module to declare depends on the webpack loader used for the file type. In a webpack configuration that pipes *.scss files through sass-loader → css-loader → style-loader, there will be no content in the imported module, and the correct module declaration would look like this:

// declaration.d.ts
declare module '*.scss';

If the loaders are configured for css-modules just extend the declaration like this:

// declaration.d.ts
declare module '*.scss' {
    const content: Record<string, string>;
    export default content;
}

Here is a complete configuration that works for me (I just spent an hour of painful trial and error on this - in case anybody runs into the same issues):

TypeScript + WebPack + Sass

webpack.config.js

module.exports = {
  //mode: "production", 
    mode: "development", devtool: "inline-source-map",

    entry: [ "./src/app.tsx"/*main*/ ], 
    output: {
        filename: "./bundle.js"  // in /dist
    },
    resolve: {
        // Add `.ts` and `.tsx` as a resolvable extension.
        extensions: [".ts", ".tsx", ".js", ".css", ".scss"]
    },
    module: {
        rules: [

            { test: /\.tsx?$/, loader: "ts-loader" }, 

            { test: /\.scss$/, use: [ 
                { loader: "style-loader" },  // to inject the result into the DOM as a style block
                { loader: "css-modules-typescript-loader"},  // to generate a .d.ts module next to the .scss file (also requires a declaration.d.ts with "declare modules '*.scss';" in it to tell TypeScript that "import styles from './styles.scss';" means to load the module "./styles.scss.d.td")
                { loader: "css-loader", options: { modules: true } },  // to convert the resulting CSS to Javascript to be bundled (modules:true to rename CSS classes in output to cryptic identifiers, except if wrapped in a :global(...) pseudo class)
                { loader: "sass-loader" },  // to convert SASS to CSS
                // NOTE: The first build after adding/removing/renaming CSS classes fails, since the newly generated .d.ts typescript module is picked up only later
            ] }, 

        ]
    }
}; 

Also put a declarations.d.ts in your project:

// We need to tell TypeScript that when we write "import styles from './styles.scss' we mean to load a module (to look for a './styles.scss.d.ts'). 
declare module '*.scss'; 

And you will need all these in your package.json's dev-dependencies:

  "devDependencies": {
    "@types/node-sass": "^4.11.0",
    "node-sass": "^4.12.0",
    "css-loader": "^1.0.0",
    "css-modules-typescript-loader": "^2.0.1",
    "sass-loader": "^7.1.0",
    "style-loader": "^0.23.1",
    "ts-loader": "^5.3.3",
    "typescript": "^3.4.4",
    "webpack": "^4.30.0",
    "webpack-cli": "^3.3.0"
  }

Then you should get a mystyle.d.ts next to your mystyle.scss containing the CSS classes you defined, which you can import as a Typescript module and use like this:

import * as styles from './mystyles.scss'; 

const foo = <div className={styles.myClass}>FOO</div>; 

The CSS will automatically be loaded (injected as a style element into the DOM) and contain cryptic identifiers instead of your CSS classes in the .scss, to isolate your styles in the page (unless you use :global(.a-global-class) { ... }).

Note that the first compile will fail whenever you add CSS classes or remove them or rename them, since the imported mystyles.d.ts is the old version and not the new version just generated during compilation. Just compile again.

Enjoy.

Just add the file typings.d.ts containing:

declare module "*.module.css";

and remember to declare your css files with 'module'. for example styles.module.css

importing:

import React from 'react';
import styles from './styles.module.css';

I'm using typescript-plugin-css-modules

npm install -D typescript-plugin-css-modules

tsconfig.json

{
  "compilerOptions": {
    "plugins": [{ "name": "typescript-plugin-css-modules" }]
  }
}

100% works

Just put a "declarations.d.ts" in your project and add the following line to it:

declare module '*.css';

Just add the declaration.d.ts file containing:

declare module "*.module.css";

Remember to declare your css files with .module.css.

Importing:

import styles from './styles.module.css'

If using Sass, replace the .css statements with .scss.

Heads Up If You Are Using tsconfig.json Path Setting

Note that if you are using these solutions in conjunction with tsconfig paths to shorten your import you will need additional configuration.

If you happen to use a path tsconfig like such:

{
  "compilerOptions": {
    "paths": {
      "style/*": [ "src/style/*" ],
    }
  }
}

So you can do:

import { header } from 'style/ui.scss';

Then you need to also add a modules resolve configuration on your webpack like such:

module.exports = {
  ...
  resolve: {
    ...
    alias: {
      style: path.resolve(__dirname, 'src', 'style')
    }
  }
}

Make sure the path is set according to your setup.

This makes it so webpack knows where to look since it thinks the new import path is actually a module so it defaults to node_modules directory. With this configuration, it knows where to look and finds it and the build works.

As per the answer @Kalle delivered, I also found that I needed to make the declaration typings discoverable within the include tsconfig option:

"include": ["./src/**/*.tsx", "./src/**/*.ts", "./typings/*.ts"]

With the typings containing the declaration.d.ts file seen in @Kalle's answer.

The above answers did'nt work for me and i was working on scss + TS + React ( if you are too, this answer is for you ). What i did was:

make a declarations.d.ts file in src folder and added following code in it

declare module "*.scss" {
  const content: { [className: string]: string };
  export = content;
}

then made a tsconfig.json file in src folder and added following code

{
  "compilerOptions": {
    "plugins": [{ "name": "typescript-plugin-css-modules" }]
  },
  //add the following
  "include": ["src/**/*.ts", "declarations.d.ts"]
}

then finally installed plugin as npm i typescript-plugin-css-modules

AND IT WORKED :)

This works for me (I am using Typescript + vite).

1. Adding this to declaration.d.ts file in project root folder

   declare module "*.module.css";
   
   declare module "*.module.scss";
   

2. Adding "declaration.d.ts" to "include" in tsconfig.json.

{
  "compilerOptions": {...},
  "include": ["src", "declaration.d.ts"],
}

This will allow the declaration to work in the src folder too not just the root folder which declarations.d.ts is located.

You can add declaration.d.ts in directly in the folder that you import styles directly but it's a bad bad idea.

In my case, I had upgraded the (major) version of NodeJS, which likely caused the problem. On the front end, I also saw an error to the effect that:

Node Sass couldn't find a binding for your current environment

The solution in my case was:

1. npm cache clean --force

2. Delete the node_modules folder for the project

3. Delete the package-lock.json file

4. npm install

After this, running npm run dev resulted in the message:

Failed to load C:\path\tsconfig.json: Missing baseUrl in compilerOptions

So the final step to resolve was:

5. Edit the tsconfig.json file and add "baseURL": ".",, under "compilerOptions":, like this:

"compilerOptions": {
    "baseUrl": ".",
    etc etc etc

Problem was resolved at this point.

Reference:

Node Sass couldn't find a binding for your current environment

In my case I solved it just commenting the loaders scss and sass:

{
                test: /\.css$/,
                use:
                    [
                        {
                            loader: 'style-loader'
                        },
                        {
                            loader: 'css-loader',
                            options: {
                                importLoaders: 1,
                                modules: true
                            }
                        }
                        // ,
                        // {
                        //     loader: 'sass-loader'
                        // }
                        // ,
                        // {
                        //     loader: 'scss-loader'
                        // }
                    ]
            }

The declare module "*.module.css"; did not affected the result.

REMEMBER: Always run

npm start 

to test these configuration changes to see if something happens**. Doing this would save me this afternoon.

In my React app, created with CRA, I had to add in react-app-env.d.ts:

declare module '*.css';

Adding this declaration in declarations.d.ts, like suggested above, did not work.

In my project, in the /src folder, there was a react-app-env.d.ts file with the contents

/// <reference types="react-scripts" />

I couldn't figure out why he was? I looked through the search where it is imported, but the search showed 0 results.And somehow I deleted it, after that I got a lot of errors:

> Cannot find module './Home.scss' or its corresponding type > declarations. TS2307 Compiled with warnings. > > Cannot find module './BlockPosts.module.css' or its corresponding type > declarations. TS2307 Compiled with warnings.

Then I restored this file and all the errors disappeared

Create a file in your project in the /src folder react-app-env.d.ts write it down

/// <reference types="react-scripts" />

And maybe you will stop making mistakes too

I had the same problem in angular, I tried to run npm audit fix and it solved my problem.