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I want to use the css-loader with the 'modules' option of webpack in a React application written in Typescript. This example was my starting point (they are using Babel, webpack and React).

webpack config

var webpack=require('webpack');
var path=require('path');
var ExtractTextPlugin=require("extract-text-webpack-plugin");

module.exports={
    entry: ['./src/main.tsx'],
    output: {
        path: path.resolve(__dirname, "target"),
        publicPath: "/assets/",
        filename: 'bundle.js'
    },
    debug: true,
    devtool: 'eval-source-map',
    plugins: [
        new webpack.optimize.DedupePlugin(),
        new webpack.optimize.UglifyJsPlugin({minimize: true})
    ],
    resolve: {
        extensions: ['', '.jsx', '.ts', '.js', '.tsx', '.css', '.less']
    },
    module: {
        loaders: [
            {
                test: /\.ts$/,
                loader: 'ts-loader'
            },
            {
                test: /\.tsx$/,
                loader: 'react-hot!ts-loader'
            }, {
                test: /\.jsx$/,
                exclude: /(node_modules|bower_components)/,
                loader: "react-hot!babel-loader"
            },
            {
                test: /\.js$/,
                exclude: /(node_modules|bower_components)/,
                loader: "babel-loader"
            }, {
                test: /\.css/,
                exclude: /(node_modules|bower_components)/,
                loader: ExtractTextPlugin.extract('style-loader', 'css-loader?modules&importLoaders=1&localIdentName=[name]__[local]___[hash:base64:5]!postcss-loader')
            }
        ]
    },
    plugins: [
        new ExtractTextPlugin("styles.css", {allChunks: true})
    ],
    postcss: function() {
        return [require("postcss-cssnext")()]
    }
}

This is a React component I want to style with an accompanying CSS file:

import React = require('react');
import styles = require('../../../css/tree.css')

class Tree extends React.Component<{}, TreeState> {
...

    render() {
        var components = this.state.components
        return (
            <div>
                <h3 className={styles.h3} >Components</h3>
                <div id="tree" className="list-group">
                    ...
                </div>
            </div>
        )
    }
}

    export = Tree

tree.css

.h3{
    color: red;
}

No matter what I'm doing (tried changing the import syntax, tried declaring the 'require' for ts-loader, described here, I always get:

Uncaught Error: Cannot find module "../../../css/tree.css"

at runtime and

error TS2307: Cannot find module '../../../css/tree.css'.

by the TS compiler. Whats happening? Seems to me that css-loader is not even emitting ICSS? Or is it ts-loader behaving wrong?

Shady
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  • `import someName = require('/some/path')` is two different kinds of invalid ;-) - are you using `import` or `require`? – Sean Vieira Jan 26 '16 at 13:19
  • What do you mean? Thats valid Typescript syntax. @SeanVieira – Shady Jan 26 '16 at 13:37
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    Yea, TypeScript adopted sort of their own module syntax while ES6 modules were still being developed. It's a hybrid between CJS and ES6 where you use `import` (like ES6) but also `require` (like CJS). TypeScript also (now) supports full ES6 syntax though as well. – James Brantly Jan 26 '16 at 13:45

5 Answers5

13

import has special meaning to TypeScript. It means that TypeScript will attempt to load and understand the thing being imported. The right way is to define require like you mentioned but then var instead of import:

var styles = require('../../../css/tree.css')`
James Brantly
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  • Do I still need to define 'require' in a d.ts? Do I have to target ES6 in my tsconfig? I get the same error @James Brantly – Shady Jan 26 '16 at 13:56
  • You need to define `require` in a d.ts, yes, otherwise TypeScript will complain that there is no `require` function. The target doesn't matter, should work the same using any target. Do you still see specifically "TS2307"? If not, then it's no longer a TypeScript error and it's webpack saying that it can't find the file (due to a bad path). – James Brantly Jan 26 '16 at 14:07
  • Yes you are right, the TS2307 is gone. The runtime error comes from webpack. How do I need to understand the path? Is it relative to the webpack.config.js? – Shady Jan 26 '16 at 14:08
  • No, it's relative to the file that's doing the requiring. – James Brantly Jan 26 '16 at 14:08
  • Right... webpack just cant find the file. I tried pulling it into the same directory as the .tsx file. No luck... Do you have a working example of Typescript+rect+modules at hand? – Shady Jan 26 '16 at 14:11
  • There are a number of examples at https://github.com/TypeStrong/ts-loader/wiki/Tutorials-&-Examples but I don't know if anything of them deals with CSS specifically. When you moved it into the same directory, did you use `require('tree.css')` or `require('./tree.css')`? The `./` is important there. – James Brantly Jan 26 '16 at 14:15
  • I found the problem: The ExtractTextPlugin was obviously throwing away the tree.css and only emits style.css. Now everything works. Thank you very much! – Shady Jan 26 '16 at 14:21
  • but please use "let" instead of "var" in a typescript environment... ;) – jebbie Apr 21 '16 at 13:27
9
  1. Declare 'require' as per ts-loader documentation.
  2. Use 'require' as generic with < any > type: require< any >("../../../css/tree.css").

*.d.ts file

declare var require: {
   <T>(path: string): T;
   (paths: string[], callback: (...modules: any[]) => void): void;
   ensure: (paths: string[], callback: (require: <T>(path: string) => T) => void) => void;
};

*.tsx file with component

const styles = require<any>("../../../css/tree.css");
...
<h3 className={styles.h3}>Components</h3>

I know it was already answered, but I was struggling with it for a while before I realized I need to use generic type specification, without that I wasn't able to access content of CSS file. (I was getting error: Property 'h3' does not exists on type '{}'.)

Martin
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  • Yeah or you can just leave away the generic in the declaration of 'require': declare var require:{(path: string): T} – Shady Mar 22 '16 at 09:30
2

I had similar problem. For me, works import:

import '../../../css/tree.css';

Webpack change this like any other normal imports. It change it to

__webpack_require__(id)

One drawback is that you lost control on style variable.

Krzysztof Sztompka
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    But I need the variable 'styles' for setting the className in the React component like:
    Can you explain further what you mean?
     – Shady Jan 26 '16 at 13:36
  • All styles are available as normal css. Then you could use it in your h3 component: `

    Components

    `     – Krzysztof Sztompka Jan 26 '16 at 13:41
  • I see what you mean, but my goal is to use CSS modules where every CSS file is scoped locally (one css file per react component). Thats why I need to assign the className programmatically – Shady Jan 26 '16 at 14:01
  • I see, I didn't find any better solution only this workaround. I will follow this question, maybe you will have a luck. – Krzysztof Sztompka Jan 26 '16 at 14:21
2

You can use https://github.com/Quramy/typed-css-modules, which creates .d.ts files from CSS Modules .css files. Please see also https://github.com/css-modules/css-modules/issues/61#issuecomment-220684795

Yosuke Kurami
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0

A bit late to game but you can create a file called tree.css.d.ts in the same folder as tree.css that has this line:

export const h3: string;

and still use the import statement import * as styles from ... and you will still getcode completion and compile time checking.

You can either manage these definition files manually or you could integrate typed-css-modules into your build pipeline (https://github.com/Quramy/typed-css-modules)

Gareth Evans
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