feat: add bundleMDXFile to make working with on-disk content easier. (#83)

* fix: read the front matter from the esbuild entry point if the user has specified one, closes #79

* feat: add `bundleMDXFile`  to make working with on-disk content easier.

BREAKING CHANGE: Update to xdm@2. This version should be safe to upgrade to without any changes, but it's possible there will be done breaking changes in some transitive dependencies that could affect you.

Author: Arcath

README.md

@@ -593,23 +593,24 @@ const {code} = await bundleMDX(mdxSource, {
 })
 ```
 
-### Replacing the entry point
+### bundleMDXFile
 
 If your MDX file is on your disk you can save some time and code by having
-`esbuild` read the file for you. To do this you can override the `entryPoints`
-settings in `esbuildOptions` with the path to your mdx source.
+`esbuild` read the file for you. To do this mdx-bundler provides the function
+`bundleMDXFile` which works the same as `bundleMDX` except it's first option is
+the path to the mdx file instead of the mdx source.
 
 ```js
-const {code, frontmatter} = await bundleMDX('', {
-  cwd: '/users/you/site/_content/pages',
-  esbuildOptions: options => {
-    options.entryPoints = ['/users/you/site/_content/pages/file.mdx']
+import {bundleMDXFile} from 'mdx-bundler'
 
-    return options
-  },
-})
+const {code, frontmatter} = await bundleMDXFile(
+  '/users/you/site/content/file.mdx',
+)
 ```
 
+`cwd` will be automatically set to the `dirname` of the given file path, you can
+still override this. All other options work the same as they do for `bundleMDX`.
+
 ### Known Issues
 
 #### Cloudflare Workers

other/sample.mdx

@@ -0,0 +1,9 @@
+---
+title: 'Sample'
+---
+
+import {Sample} from './sample-component'
+
+This is a sample mdx file that should demo mdx-bundlers features.
+
+<Sample />

package.json

@@ -40,29 +40,29 @@
     "validate": "kcd-scripts validate"
   },
   "dependencies": {
-    "@babel/runtime": "^7.14.6",
+    "@babel/runtime": "^7.15.3",
     "@esbuild-plugins/node-resolve": "^0.1.4",
     "@fal-works/esbuild-plugin-global-externals": "^2.1.2",
     "gray-matter": "^4.0.3",
-    "remark-frontmatter": "^3.0.0",
+    "remark-frontmatter": "^4.0.0",
     "remark-mdx-frontmatter": "^1.0.1",
     "uuid": "^8.3.2",
-    "xdm": "^1.12.2"
+    "xdm": "^2.0.0"
   },
   "peerDependencies": {
     "esbuild": "0.11.x || 0.12.x"
   },
   "devDependencies": {
     "@testing-library/react": "^12.0.0",
     "@types/jsdom": "^16.2.13",
-    "@types/react": "^17.0.14",
+    "@types/react": "^17.0.17",
     "@types/react-dom": "^17.0.9",
     "@types/uuid": "^8.3.1",
     "c8": "^7.8.0",
     "cross-env": "^7.0.3",
-    "esbuild": "^0.12.15",
-    "jsdom": "^16.6.0",
-    "kcd-scripts": "^11.1.0",
+    "esbuild": "^0.12.20",
+    "jsdom": "^16.7.0",
+    "kcd-scripts": "^11.2.0",
     "left-pad": "^1.3.0",
     "mdx-test-data": "^1.0.1",
     "react": "^17.0.2",

src/__tests__/index.js

@@ -7,7 +7,7 @@ import React from 'react'
 import rtl from '@testing-library/react'
 import leftPad from 'left-pad'
 import {remarkMdxImages} from 'remark-mdx-images'
-import {bundleMDX} from '../index.js'
+import {bundleMDX, bundleMDXFile} from '../index.js'
 import {getMDXComponent} from '../client.js'
 
 const {render} = rtl
@@ -500,4 +500,22 @@ This is the rest of the content
   assert.equal((matter.excerpt ? matter.excerpt : '').trim(), 'Some excerpt')
 })
 
+test('specify a file using bundleMDXFile', async () => {
+  const {frontmatter} = await bundleMDXFile(
+    path.join(process.cwd(), 'other', 'sample.mdx'),
+    {
+      esbuildOptions: options => {
+        options.loader = {
+          ...options.loader,
+          '.png': 'dataurl',
+        }
+
+        return options
+      },
+    },
+  )
+
+  assert.equal(frontmatter.title, 'Sample')
+})
+
 test.run()

src/index.js

@@ -26,7 +26,7 @@ async function bundleMDX(
     esbuildOptions = options => options,
     globals = {},
     cwd = path.join(process.cwd(), `__mdx_bundler_fake_dir__`),
-    grayMatterOptions = options => options
+    grayMatterOptions = options => options,
   } = {},
 ) {
   /* c8 ignore start */
@@ -42,8 +42,6 @@ async function bundleMDX(
   const [{default: xdmESBuild}] = await Promise.all([
     await import('xdm/esbuild.js'),
   ])
-  // extract the frontmatter
-  const matter = grayMatter(mdxSource, grayMatterOptions({}))
 
   const entryPath = path.join(cwd, `./_mdx_bundler_entry_point-${uuid()}.mdx`)
 
@@ -168,6 +166,24 @@ async function bundleMDX(
     minify: true,
   })
 
+  // Extract the front matter from the source or the entry point
+
+  /** @type grayMatter.GrayMatterFile<any> */
+  let matter
+
+  // We have to be a bit specific here to ensure type safety
+  if (
+    buildOptions.entryPoints &&
+    Array.isArray(buildOptions.entryPoints) &&
+    buildOptions.entryPoints[0] !== entryPath
+  ) {
+    //The user has replaced the entrypoint, we can assume this means `mdxSource` is empty
+
+    matter = grayMatter.read(buildOptions.entryPoints[0], grayMatterOptions({}))
+  } else {
+    matter = grayMatter(mdxSource, grayMatterOptions({}))
+  }
+
   const bundled = await esbuild.build(buildOptions)
 
   if (bundled.outputFiles) {
@@ -179,7 +195,7 @@ async function bundleMDX(
       code: `${code};return Component.default;`,
       frontmatter: matter.data,
       errors: bundled.errors,
-      matter
+      matter,
     }
   }
 
@@ -198,7 +214,7 @@ async function bundleMDX(
       code: `${code};return Component.default;`,
       frontmatter: matter.data,
       errors: bundled.errors,
-      matter
+      matter,
     }
   }
 
@@ -207,4 +223,35 @@ async function bundleMDX(
   )
 }
 
-export {bundleMDX}
+/**
+ *
+ * @param {string} mdxPath - The file path to bundle.
+ * @param {import('./types').BundleMDXOptions} options
+ * @returns
+ */
+async function bundleMDXFile(
+  mdxPath,
+  {
+    files = {},
+    xdmOptions = options => options,
+    esbuildOptions = options => options,
+    globals = {},
+    cwd,
+    grayMatterOptions = options => options,
+  } = {},
+) {
+  return bundleMDX('', {
+    files,
+    xdmOptions,
+    esbuildOptions: options => {
+      options.entryPoints = [mdxPath]
+
+      return esbuildOptions(options)
+    },
+    globals,
+    cwd: cwd ? cwd : path.dirname(mdxPath),
+    grayMatterOptions,
+  })
+}
+
+export {bundleMDX, bundleMDXFile}