astro/packages/integrations/mdx/src/index.ts
2023-09-14 20:05:38 +08:00

268 lines
9.7 KiB
TypeScript

import { markdownConfigDefaults, setVfileFrontmatter } from '@astrojs/markdown-remark';
import type { PluggableList } from '@mdx-js/mdx/lib/core.js';
import type { AstroIntegration, ContentEntryType, HookParameters, SSRError } from 'astro';
import astroJSXRenderer from 'astro/jsx/renderer.js';
import { parse as parseESM } from 'es-module-lexer';
import fs from 'node:fs/promises';
import { fileURLToPath } from 'node:url';
import type { Options as RemarkRehypeOptions } from 'remark-rehype';
import { VFile } from 'vfile';
import type { Plugin as VitePlugin } from 'vite';
import { createMdxProcessor } from './plugins.js';
import type { OptimizeOptions } from './rehype-optimize-static.js';
import {
ASTRO_IMAGE_ELEMENT,
ASTRO_IMAGE_IMPORT,
USES_ASTRO_IMAGE_FLAG,
} from './remark-images-to-component.js';
import { getFileInfo, ignoreStringPlugins, parseFrontmatter } from './utils.js';
export type MdxOptions = Omit<typeof markdownConfigDefaults, 'remarkPlugins' | 'rehypePlugins'> & {
extendMarkdownConfig: boolean;
recmaPlugins: PluggableList;
// Markdown allows strings as remark and rehype plugins.
// This is not supported by the MDX compiler, so override types here.
remarkPlugins: PluggableList;
rehypePlugins: PluggableList;
remarkRehype: RemarkRehypeOptions;
optimize: boolean | OptimizeOptions;
};
type SetupHookParams = HookParameters<'astro:config:setup'> & {
// `addPageExtension` and `contentEntryType` are not a public APIs
// Add type defs here
addPageExtension: (extension: string) => void;
addContentEntryType: (contentEntryType: ContentEntryType) => void;
};
export default function mdx(partialMdxOptions: Partial<MdxOptions> = {}): AstroIntegration {
return {
name: '@astrojs/mdx',
hooks: {
'astro:config:setup': async (params) => {
const {
updateConfig,
config,
addPageExtension,
addContentEntryType,
command,
addRenderer,
} = params as SetupHookParams;
addRenderer(astroJSXRenderer);
addPageExtension('.mdx');
addContentEntryType({
extensions: ['.mdx'],
async getEntryInfo({ fileUrl, contents }: { fileUrl: URL; contents: string }) {
const parsed = parseFrontmatter(contents, fileURLToPath(fileUrl));
return {
data: parsed.data,
body: parsed.content,
slug: parsed.data.slug,
rawData: parsed.matter,
};
},
contentModuleTypes: await fs.readFile(
new URL('../template/content-module-types.d.ts', import.meta.url),
'utf-8'
),
// MDX can import scripts and styles,
// so wrap all MDX files with script / style propagation checks
handlePropagation: true,
});
const extendMarkdownConfig =
partialMdxOptions.extendMarkdownConfig ?? defaultMdxOptions.extendMarkdownConfig;
const mdxOptions = applyDefaultOptions({
options: partialMdxOptions,
defaults: markdownConfigToMdxOptions(
extendMarkdownConfig ? config.markdown : markdownConfigDefaults
),
});
let processor: ReturnType<typeof createMdxProcessor>;
updateConfig({
vite: {
plugins: [
{
name: '@mdx-js/rollup',
enforce: 'pre',
configResolved(resolved) {
processor = createMdxProcessor(mdxOptions, {
sourcemap: !!resolved.build.sourcemap,
importMetaEnv: { SITE: config.site, ...resolved.env },
});
// HACK: move ourselves before Astro's JSX plugin to transform things in the right order
const jsxPluginIndex = resolved.plugins.findIndex((p) => p.name === 'astro:jsx');
if (jsxPluginIndex !== -1) {
const myPluginIndex = resolved.plugins.findIndex(
(p) => p.name === '@mdx-js/rollup'
);
if (myPluginIndex !== -1) {
const myPlugin = resolved.plugins[myPluginIndex];
// @ts-ignore-error ignore readonly annotation
resolved.plugins.splice(myPluginIndex, 1);
// @ts-ignore-error ignore readonly annotation
resolved.plugins.splice(jsxPluginIndex, 0, myPlugin);
}
}
},
// Override transform to alter code before MDX compilation
// ex. inject layouts
async transform(_, id) {
if (!id.endsWith('.mdx')) return;
// Read code from file manually to prevent Vite from parsing `import.meta.env` expressions
const { fileId } = getFileInfo(id, config);
const code = await fs.readFile(fileId, 'utf-8');
const { data: frontmatter, content: pageContent } = parseFrontmatter(code, id);
const vfile = new VFile({ value: pageContent, path: id });
// Ensure `data.astro` is available to all remark plugins
setVfileFrontmatter(vfile, frontmatter);
try {
const compiled = await processor.process(vfile);
return {
code: escapeViteEnvReferences(String(compiled.value)),
map: compiled.map,
};
} catch (e: any) {
const err: SSRError = e;
// For some reason MDX puts the error location in the error's name, not very useful for us.
err.name = 'MDXError';
err.loc = { file: fileId, line: e.line, column: e.column };
// For another some reason, MDX doesn't include a stack trace. Weird
Error.captureStackTrace(err);
throw err;
}
},
},
{
name: '@astrojs/mdx-postprocess',
// These transforms must happen *after* JSX runtime transformations
transform(code, id) {
if (!id.endsWith('.mdx')) return;
const [moduleImports, moduleExports] = parseESM(code);
// Fragment import should already be injected, but check just to be safe.
const importsFromJSXRuntime = moduleImports
.filter(({ n }) => n === 'astro/jsx-runtime')
.map(({ ss, se }) => code.substring(ss, se));
const hasFragmentImport = importsFromJSXRuntime.some((statement) =>
/[\s,{](Fragment,|Fragment\s*})/.test(statement)
);
if (!hasFragmentImport) {
code = 'import { Fragment } from "astro/jsx-runtime"\n' + code;
}
const { fileUrl, fileId } = getFileInfo(id, config);
if (!moduleExports.find(({ n }) => n === 'url')) {
code += `\nexport const url = ${JSON.stringify(fileUrl)};`;
}
if (!moduleExports.find(({ n }) => n === 'file')) {
code += `\nexport const file = ${JSON.stringify(fileId)};`;
}
if (!moduleExports.find(({ n }) => n === 'Content')) {
// If have `export const components`, pass that as props to `Content` as fallback
const hasComponents = moduleExports.find(({ n }) => n === 'components');
const usesAstroImage = moduleExports.find(
({ n }) => n === USES_ASTRO_IMAGE_FLAG
);
let componentsCode = `{ Fragment${
hasComponents ? ', ...components' : ''
}, ...props.components,`;
if (usesAstroImage) {
componentsCode += ` ${JSON.stringify(ASTRO_IMAGE_ELEMENT)}: ${
hasComponents ? 'components.img ?? ' : ''
} props.components?.img ?? ${ASTRO_IMAGE_IMPORT}`;
}
componentsCode += ' }';
// Make `Content` the default export so we can wrap `MDXContent` and pass in `Fragment`
code = code.replace('export default MDXContent;', '');
code += `\nexport const Content = (props = {}) => MDXContent({
...props,
components: ${componentsCode},
});
export default Content;`;
}
// mark the component as an MDX component
code += `\nContent[Symbol.for('mdx-component')] = true`;
// Ensures styles and scripts are injected into a `<head>`
// When a layout is not applied
code += `\nContent[Symbol.for('astro.needsHeadRendering')] = !Boolean(frontmatter.layout);`;
code += `\nContent.moduleId = ${JSON.stringify(id)};`;
if (command === 'dev') {
// TODO: decline HMR updates until we have a stable approach
code += `\nif (import.meta.hot) {
import.meta.hot.decline();
}`;
}
return { code: escapeViteEnvReferences(code), map: null };
},
},
] as VitePlugin[],
},
});
},
},
};
}
const defaultMdxOptions = {
extendMarkdownConfig: true,
recmaPlugins: [],
};
function markdownConfigToMdxOptions(markdownConfig: typeof markdownConfigDefaults): MdxOptions {
return {
...defaultMdxOptions,
...markdownConfig,
remarkPlugins: ignoreStringPlugins(markdownConfig.remarkPlugins),
rehypePlugins: ignoreStringPlugins(markdownConfig.rehypePlugins),
remarkRehype: (markdownConfig.remarkRehype as any) ?? {},
optimize: false,
};
}
function applyDefaultOptions({
options,
defaults,
}: {
options: Partial<MdxOptions>;
defaults: MdxOptions;
}): MdxOptions {
return {
syntaxHighlight: options.syntaxHighlight ?? defaults.syntaxHighlight,
extendMarkdownConfig: options.extendMarkdownConfig ?? defaults.extendMarkdownConfig,
recmaPlugins: options.recmaPlugins ?? defaults.recmaPlugins,
remarkRehype: options.remarkRehype ?? defaults.remarkRehype,
gfm: options.gfm ?? defaults.gfm,
smartypants: options.smartypants ?? defaults.smartypants,
remarkPlugins: options.remarkPlugins ?? defaults.remarkPlugins,
rehypePlugins: options.rehypePlugins ?? defaults.rehypePlugins,
shikiConfig: options.shikiConfig ?? defaults.shikiConfig,
optimize: options.optimize ?? defaults.optimize,
};
}
// Converts the first dot in `import.meta.env` to its Unicode escape sequence,
// which prevents Vite from replacing strings like `import.meta.env.SITE`
// in our JS representation of loaded Markdown files
function escapeViteEnvReferences(code: string) {
return code.replace(/import\.meta\.env/g, 'import\\u002Emeta.env');
}