modernize 2.0 preact build (#1269)

This sets us up to modernize all of our builds by implementing microbundle on the preact package. This produces a commonjs build that is left as main because that's what people currently expect, an es build that gets used by webpack, etc under the module key, and a true es modern build that will get used conditionally by node v14 native esm when `import` is used. When `require` is used in v14, the commonjs build gets used.

package.json

@@ -16,7 +16,7 @@
     "node": "12.x"
   },
   "scripts": {
-    "build": "r -f cjs,esm -o dist --exclude 'babel-plugin-*,create-mdx,*loader,mdx,parcel-plugin-mdx,remark-*,*util'",
+    "build": "r -f cjs,esm -o dist --exclude 'babel-plugin-*,create-mdx,*loader,mdx,parcel-plugin-mdx,remark-*,*util,@mdx-js/preact' && yarn workspace @mdx-js/preact build",
     "clean": "lerna exec \"rimraf dist node_modules\" && gatsby clean",
     "docs": "gatsby develop",
     "docs-build": "gatsby build",
@@ -36,6 +36,7 @@
     "test-parser": "nyc --reporter lcov tape packages/remark-mdx/test/index.js",
     "test-types": "lerna run test-types"
   },
+  "dependencies": {},
   "devDependencies": {
     "@babel/core": "7.10.5",
     "@babel/plugin-syntax-jsx": "7.10.4",
@@ -71,6 +72,7 @@
     "lerna": "3.22.1",
     "lint-staged": "10.2.11",
     "memory-fs": "0.5.0",
+    "microbundle": "^0.12.3",
     "prettier": "2.0.5",
     "prettier-plugin-pkg": "0.7.0",
     "react": "16.13.1",
@@ -136,6 +138,5 @@
     "bracketSpacing": false,
     "semi": false,
     "trailingComma": "none"
-  },
-  "dependencies": {}
+  }
 }

packages/preact/package.json

@@ -15,11 +15,16 @@
     "Tim Neutkens <[email protected]>",
     "Matija Marohnić <[email protected]>",
     "Titus Wormer <[email protected]> (https://wooorm.com)",
-    "JounQin <[email protected]> (https://www.1stg.me)"
+    "JounQin <[email protected]> (https://www.1stg.me)",
+    "Chris Biscardi <[email protected]> (https://www.christopherbiscardi.com)"
   ],
   "license": "MIT",
-  "main": "dist/cjs.js",
-  "module": "dist/esm.js",
+  "main": "dist/mdx-preact.js",
+  "module": "dist/mdx-preact.es.js",
+  "exports": {
+    "import": "./dist/mdx-preact.mjs",
+    "require": "./dist/mdx-preact.js"
+  },
   "files": [
     "dist"
   ],
@@ -31,12 +36,17 @@
     "remark",
     "mdxast"
   ],
+  "scripts": {
+    "build": "microbundle -f modern,es,cjs src/index.js"
+  },
   "peerDependencies": {
     "preact": "^10.4.6"
   },
   "devDependencies": {
     "preact": "10.4.1",
     "preact-render-to-string": "5.1.10"
   },
-  "gitHead": "bf7deab69996449cb99c2217dff75e65855eb2c1"
+  "esmodule": "dist/foo.mjs",
+  "gitHead": "bf7deab69996449cb99c2217dff75e65855eb2c1",
+  "source": ""
 }