sass-transformer-inside-gb.js

/** @format */

/**
 * Parts of this source were derived and modified from react-native-sass-transformer,
 * released under the MIT license.
 *
 * https://github.com/kristerkari/react-native-sass-transformer
 *
 * The MIT License (MIT)

 * Copyright (c) 2018 Krister Kari

 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

// TODO: create a new npm package with this transformer, or extend 'react-native-sass-transformer'

const fs = require( 'fs' );

const sass = require( 'node-sass' );
const semver = require( 'semver' );
const css2rn = require( 'css-to-react-native-transform' ).default;
const path = require( 'path' );

let upstreamTransformer = null;

const reactNativeVersionString = require( 'react-native/package.json' ).version;
const reactNativeMinorVersion = semver( reactNativeVersionString ).minor;

if ( reactNativeMinorVersion >= 56 ) {
	upstreamTransformer = require( 'metro/src/reactNativeTransformer' );
} else if ( reactNativeMinorVersion >= 52 ) {
	upstreamTransformer = require( 'metro/src/transformer' );
} else if ( reactNativeMinorVersion >= 47 ) {
	upstreamTransformer = require( 'metro-bundler/src/transformer' );
} else if ( reactNativeMinorVersion === 46 ) {
	upstreamTransformer = require( 'metro-bundler/build/transformer' );
} else {
	// handle RN <= 0.45
	const oldUpstreamTransformer = require( 'react-native/packager/transformer' );
	upstreamTransformer = {
		transform( { src, filename, options } ) {
			return oldUpstreamTransformer.transform( src, filename, options );
		},
	};
}

// TODO: need to find a way to pass the include paths and the default asset files via some config
const autoImportIncludePaths = [
	path.join( path.dirname( __filename ), '../assets/stylesheets' ),
];
const autoImportAssets = [
	'_colors.scss',
	'_breakpoints.scss',
	'_variables.scss',
	'_mixins.scss',
	'_animations.scss',
	'_z-index.scss',
];
const imports = '@import "' + autoImportAssets.join( '";\n@import "' ) + '";\n\n';

// Iterate through the include paths and extensions to find the file variant
function findVariant( name, extensions, includePaths ) {
	for ( let i = 0; i < includePaths.length; i++ ) {
		const includePath = includePaths[ i ];

		// try to find the file iterating through the extensions, in order.
		const foundExtention = extensions.find( ( extension ) => {
			const fname = includePath + '/' + name + extension;
			return fs.existsSync( fname );
		} );

		if ( foundExtention ) {
			return includePath + '/' + name + foundExtention;
		}
	}

	return false;
}

// Transform function taken from react-native-sass-transformer but extended to have more include paths
//  and detect and use RN platform specific file variants
function transform( src, filename, options ) {
	if ( typeof src === 'object' ) {
		// handle RN >= 0.46
		( { src, filename, options } = src );
	}

	const exts = [
		// add the platform specific extension, first in the array to take precedence
		options.platform === 'android' ? '.android.scss' : '.ios.scss',
		'.native.scss',
		'.scss',
	];

	if ( filename.endsWith( '.scss' ) || filename.endsWith( '.sass' ) ) {
		const result = sass.renderSync( {
			data: src,
			includePaths: [ path.dirname( filename ), ...autoImportIncludePaths ],
			importer( url /*, prev, done */ ) {
				// url is the path in import as is, which LibSass encountered.
				// prev is the previously resolved path.
				// done is an optional callback, either consume it or return value synchronously.
				// this.options contains this options hash, this.callback contains the node-style callback

				const urlPath = path.parse( url );
				const importerOptions = this.options;
				const incPaths = importerOptions.includePaths.slice( 0 ).split( ':' );
				if ( urlPath.dir.length > 0 ) {
					incPaths.unshift( path.resolve( path.dirname( filename ), urlPath.dir ) ); // add the file's dir to the search array
				}
				const f = findVariant( urlPath.name, exts, incPaths );

				if ( f ) {
					return { file: f };
				}

				return new Error( url + ' could not be resolved in ' + incPaths );
			},
		} );
		const css = result.css.toString();
		const cssObject = css2rn( css, { parseMediaQueries: true } );

		return upstreamTransformer.transform( {
			src: 'module.exports = ' + JSON.stringify( cssObject ),
			filename,
			options,
		} );
	}
	return upstreamTransformer.transform( { src, filename, options } );
}

module.exports.transform = function( { src, filename, options } ) {
	if ( filename.endsWith( '.scss' ) || filename.endsWith( '.sass' ) ) {
		// "auto-import" the stylesheets the GB webpack config imports
		src = imports + src;
		return transform( { src, filename, options } );
	}
	return upstreamTransformer.transform( { src, filename, options } );
};