astro/scripts/utils/svelte-plugin.js

// @ts-nocheck
import { compile } from 'svelte/compiler';
import { relative, isAbsolute, join, dirname } from 'path';
import { promises as fs } from 'fs';

const convertMessage = ({ message, start, end, filename, frame }) => ({
    text: message,
    location: start && end && {
        file: filename,
        line: start.line,
        column: start.column,
        length: start.line === end.line ? end.column - start.column : 0,
        lineText: frame,
    },
})

const handleLoad = async (args, generate) => {
    const { path } = args;
    const source = await fs.readFile(path, 'utf8');
    const filename = relative(process.cwd(), path)

    try {
        let compileOptions = { css: false, generate, hydratable: true };

        let { js, warnings } = compile(source, { ...compileOptions, filename })
        let contents = js.code + `\n//# sourceMappingURL=` + js.map.toUrl()

        return { loader: 'js', contents, resolveDir: dirname(path), warnings: warnings.map(w => convertMessage(w)) };
    } catch (e) {
        return { errors: [convertMessage(e)] }
    }
}

export default function sveltePlugin() {
    return {
        name: 'svelte-esbuild',
        setup(build) {
                build.onResolve({ filter: /\.svelte$/ }, args => {
                    let path = args.path.replace(/\.(?:client|server)/, '');
                    path = isAbsolute(path) ? path : join(args.resolveDir, path)
                    
                    if (/\.client\.svelte$/.test(args.path)) {
                        return {
                            path,
                            namespace: 'svelte:client',
                        }
                    }

                    if (/\.server\.svelte$/.test(args.path)) {
                        return {
                            path,
                            namespace: 'svelte:server',
                        }
                    }
                });
            build.onLoad({ filter: /.*/, namespace: 'svelte:client' }, (args) => handleLoad(args, 'dom'))
            build.onLoad({ filter: /.*/, namespace: 'svelte:server' }, (args) => handleLoad(args, 'ssr'))
        },
    }
}