budarin / ts-css-loader

Webpack loader to generate typescript definitions for css-modules for isomorphic apps

@budarin/ts-css-loader

This loader is a fork of the well-known loader typings-for-css-modules-loader

The purpose of creating yet another typescript generation loader for css-modules is the ability to use it in an isomorphic application in conjunction with style-loader/usable(is used in browser to use or unse component's stylesheets) and fake-style-loader(is used on server side to get source css from component's stylesheet).

style-loader/usable adds 2 methods to the css-modules interface:

• use: Function
• unuse: Function

fake-style-loader adds properties to the css-modules interface:

• source: String
• all classnames into default exported object

Installation

Install via npm npm install --save-dev @budarin/ts-css-loader

Options

All options are available only when the parameter modules set to true(see options for css-loader)

Name	Type	Default	Description
EOL	{String}	CRLF	{'CRLF', 'LF'}
onlyNamedExport	{Boolean}	false	Export only named items of interface
browser	{Boolean}	false	Add use and unuse methods to interface and all classnames in flat view
server	{Boolean}	false	Add source property to interface
tabWidth	{Number}	4	Set tabWidth for indentation
silent	{Boolean}	false	To silence the loader
banner	{Boolean}	false	Adds a "banner" prefix to each generated *.d.ts

the other parameters are the same as the css-loader:

This loader should be used instead of` css-loader ' because inside it uses it.

An example of using webpack.config:

    test: /\.css$/,
    use: [
        {
            loader: 'style-loader',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
            },
        }
    ]

for style file app.css:

.foo {
    color: red;
}

the loader will generate a type definition:

declare interface IAppCss {
    readonly foo: string;
}
declare const styles: IAppCss;

export default styles;

EOL

Default: 'CRLF'.

Defines a line separator in type definition file and must be equal to the parameter set in git to prevent constant overwriting of type definition file. This parameter can take one of these acronims {'CRLF','LF}'

    test: /\.css$/,
    use: [
        {
            loader: 'style-loader',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
                EOL: 'LF'
            }
        }
    ]

onlyNamedExport

Default: false.

This parameter determines whether only named exports are present in the module interface

    test: /\.css$/,
    use: [
        {
            loader: 'style-loader',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
                onlyNamedExport: true
            }
        }
    ]

output:

export const foo: string;

browser

Default: false.

The parameter determines the presence of style-loader/disable methods in the interface: use and unuse.

    test: /\.css$/,
    use: [
        {
            loader: 'style-loader/usable',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
                browser: true
            }
        }
    ]

output:

declare interface IAppCss {
    readonly locals: {
        readonly foo: string;
    };
    readonly use: Function;
    readonly unuse: Function;
}
declare const styles: IAppCss;

export default styles;

server

Default: false.

Determines the presence of the interface property source: string for fake-style-loader and presene all css classes in default export

    test: /\.css$/,
    use: [
        {
            loader: 'fake-style-loader',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
                server: true
            }
        }
    ]

output:

declare interface IAppCss {
    readonly foo: string;
    readonly source: string;
}
declare const styles: IAppCss;

export default styles;

tabWidth

Default: 4.

Number of spaces it should use per tab

silent

Default: false.

To silence the loader because you get annoyed by its warnings or for other reasons, you can simply pass the "silent" query to the loader and it will shut up. e.g.:

    test: /\.css$/,
    use: [
        {
            loader: 'style-loader',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: false,
            }
        }
    ]

banner

Default: false..

To add a "banner" prefix to each generated *.d.ts file, you can pass a string to this option as shown below. The prefix is quite literally prefixed into the generated file, so please ensure it conforms to the type definition syntax.

    test: /\.css$/,
    use: [
        {
            loader: 'style-loader',
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
                banner: "// This file is automatically generated file.\n// Please do not change this file!"
            }
        }
    ]

output:

// This file is automatically generated file
// Please do not change this file!"
declare interface IAppCss {
    readonly locals: {
        readonly foo: string;
    };
}
declare const styles: IAppCss;

export default styles;

For isomorphic applications, you can use the following configuration:

    test: /\.css$/,
    use: [
        {
            loader: ...
        },
        {
            loader: '@budarin/ts-css-loader',
            options: {
                modules: true,
                browser: true,
                server: true
            }
        }
    ]

output:

declare interface IAppCss {
    readonly locals: {
        readonly foo: string;
    };
    readonly use: Function;
    readonly unuse: Function;
    readonly source: string;
}
declare const styles: IAppCss;

export default styles;

using onlyNamedExport with the camelCase

Using the onlyNamedExport as well as the camelCase options the generated file will look as follow:

export const someClass: string;
export const someOtherClass: string;
export const someClassSayWhat: string;

Example in Visual Studio Code

If you encounter the following errors:

error TS1192: Module '"xxxxx/xxxx/src/style.sass"' has no default export.

maybe you should export the styles as following:

import * as styles from './style.sass';

Support

As the loader just acts as an intermediary it can handle all kind of css preprocessors (sass, scss, stylus, less, ...). The only requirement is that those preprocessors have proper webpack loaders defined - meaning they can already be loaded by webpack anyways.

Requirements

The loader uses css-loader(https://github.com/webpack/css-loader) under the hood. Thus it is a peer-dependency and the expected loader to create CSS Modules.

Known issues

Webpack rebuilds / builds slow

As the loader generates typing files, it is wise to tell webpack to ignore them. The fix is luckily very simple. Webpack ships with a "WatchIgnorePlugin" out of the box. Simply add this to your webpack plugins:

plugins: [
    new webpack.WatchIgnorePlugin([
      /css\.d\.ts$/
    ]),
    ...
  ]

where css is the file extension of your style files. If you use sass you need to put sass here instead. If you use less, stylus or any other style language use their file ending.

Typescript doesnt find the typings

As the webpack process is independent from your typescript "runtime" it may take a while for typescript to pick up the typings. Any hints on how this could be fixed deterministically are welcome!