svelte.config.js

const sass = require('node-sass')
const { preprocess, createEnv, readConfigFile } = require('@pyoner/svelte-ts-preprocess')
// const stylus = require('stylus')

const env = createEnv()
const compilerOptions = readConfigFile(env)
const opts = {
    env,
    compilerOptions: {
        ...compilerOptions,
        allowNonTsExtensions: true
    },
    hideErrors: true
}

// Needed for the svelte-vscode extension
module.exports = {
    preprocess: {
        style: ({ content, attributes, filename }) => {
            if (attributes.type !== 'text/scss' && attributes.lang !== 'scss') return

            // // Needed because svelte indents the style content
            // content = content.replace(/^    /gm, '')

            return new Promise((resolve, reject) => {
                sass.render(
                    {
                        file: filename,
                        data: content,
                        includePaths: ['src', 'node_modules'],
                        sourceMap: true,
                        // indentedSyntax: true,
                        // indentWidth: 4,
                        outFile: filename + '.css'
                    },
                    (err, result) => {
                        if (err) return reject(err)
                        resolve({
                            code: result.css.toString(),
                            map: JSON.parse(result.map.toString()),
                            dependencies: result.stats.includedFiles
                        })
                    }
                )
            })

            // if (attributes.lang !== 'stylus') return

            // return new Promise((resolve, reject) => {
            //     const style = stylus(content, {
            //         filename,
            //         sourcemap: true
            //     })

            //     style.render((err, css) => {
            //         if (err) reject(err)

            //         resolve({ code: css, /*dependencies: style.deps(),*/ map: style.sourcemap })
            //     })
            // })
        },
        script: preprocess(opts).script
        // script: ({ content, attributes, filename }) => {
        //     if (attributes.lang !== 'typescript') return

        //     return new Promise((resolve, reject) => {
        //         try {
        //             const result = sucrase.transform(content, {
        //                 transforms: ['typescript'],
        //                 filePath: filename,
        //                 sourceMapOptions: {
        //                     compiledFilename: filename
        //                 }
        //             })

        //             resolve({ code: result.code, map: result.sourceMap })
        //         } catch (e) {
        //             reject(e)
        //         }
        //     })
        // }
    }
}