Replace buble with babel

Author: eliihen

package.json

@@ -44,8 +44,9 @@
   "dependencies": {
     "@babel/core": "^7.1.6",
     "@babel/plugin-proposal-class-properties": "7.1.0",
-    "@babel/plugin-syntax-jsx": "^7.0.0",
     "@babel/polyfill": "^7.0.0",
+    "@babel/preset-env": "^7.2.0",
+    "@babel/preset-react": "^7.0.0",
     "asyncro": "^3.0.0",
     "autoprefixer": "^9.0.0",
     "babel-plugin-transform-async-to-promises": "^0.8.1",
@@ -57,8 +58,7 @@
     "gzip-size": "^5.0.0",
     "pretty-bytes": "^5.1.0",
     "rollup": "^0.67.3",
-    "rollup-plugin-babel": "^4.1.0-0",
-    "rollup-plugin-buble": "^0.19.4",
+    "rollup-plugin-babel": "^4.0.3",
     "rollup-plugin-bundle-size": "^1.0.1",
     "rollup-plugin-commonjs": "^9.0.0",
     "rollup-plugin-es3": "^1.1.0",
@@ -79,7 +79,6 @@
   "devDependencies": {
     "@babel/cli": "^7.1.5",
     "@babel/node": "^7.0.0",
-    "@babel/preset-env": "^7.1.6",
     "babel-core": "^7.0.0-bridge.0",
     "babel-jest": "^23.6.0",
     "directory-tree": "^2.1.0",

src/index.js

@@ -9,7 +9,6 @@ import { rollup, watch } from 'rollup';
 import commonjs from 'rollup-plugin-commonjs';
 import babel from 'rollup-plugin-babel';
 import nodeResolve from 'rollup-plugin-node-resolve';
-import buble from 'rollup-plugin-buble';
 import { terser } from 'rollup-plugin-terser';
 import postcss from 'rollup-plugin-postcss';
 import alias from 'rollup-plugin-strict-alias';
@@ -152,7 +151,7 @@ export default async function microbundle(options) {
 	for (let i = 0; i < entries.length; i++) {
 		for (let j = 0; j < formats.length; j++) {
 			steps.push(
-				createConfig(options, entries[i], formats[j], i === 0 && j === 0),
+				await createConfig(options, entries[i], formats[j], i === 0 && j === 0),
 			);
 		}
 	}
@@ -226,7 +225,7 @@ export default async function microbundle(options) {
 	);
 }
 
-function createConfig(options, entry, format, writeMeta) {
+async function createConfig(options, entry, format, writeMeta) {
 	let { pkg } = options;
 
 	let external = ['dns', 'fs', 'path', 'url'].concat(
@@ -377,26 +376,46 @@ function createConfig(options, entry, format, writeMeta) {
 							},
 						}),
 					!useTypescript && flow({ all: true, pretty: true }),
-					// Only used for async await
-					babel({
-						// We mainly use bublé to transpile JS and only use babel to
-						// transpile down `async/await`. To prevent conflicts with user
-						// supplied configurations we set this option to false. Note
-						// that we never supported using custom babel configs anyway.
-						babelrc: false,
-						exclude: 'node_modules/**',
-						plugins: [
-							require.resolve('@babel/plugin-syntax-jsx'),
-							[
-								require.resolve('babel-plugin-transform-async-to-promises'),
-								{ inlineHelpers: true, externalHelpers: true },
-							],
-							[
-								require.resolve('@babel/plugin-proposal-class-properties'),
-								{ loose: true },
-							],
-						],
-					}),
+					babel(
+						(await isFile('.babelrc')) || (await isFile('.babelrc.js'))
+							? {
+									// Babelrc exists, allow project to configure babel
+									exclude: 'node_modules/**',
+							  }
+							: {
+									// No babelrc exists, use default config
+									exclude: 'node_modules/**',
+									presets: [
+										['@babel/preset-react', { pragma: options.jsx }],
+										[
+											'@babel/preset-env',
+											{
+												loose: true,
+												exclude: [
+													// Disabling preset-env async/await support so we can use
+													// plugin-transform-async-to-promises
+													'transform-async-to-generator',
+													'transform-regenerator',
+												],
+											},
+										],
+									],
+									plugins: [
+										[
+											require.resolve(
+												'babel-plugin-transform-async-to-promises',
+											),
+											{ inlineHelpers: true, externalHelpers: true },
+										],
+										[
+											require.resolve(
+												'@babel/plugin-proposal-class-properties',
+											),
+											{ loose: true },
+										],
+									],
+							  },
+					),
 					{
 						// Custom plugin that removes shebang from code because newer
 						// versions of bublé bundle their own private version of `acorn`
@@ -419,15 +438,6 @@ function createConfig(options, entry, format, writeMeta) {
 							};
 						},
 					},
-					buble({
-						exclude: 'node_modules/**',
-						jsx: options.jsx || 'h',
-						objectAssign: options.assign || 'Object.assign',
-						transforms: {
-							dangerousForOf: true,
-							dangerousTaggedTemplateString: true,
-						},
-					}),
 					// We should upstream this to rollup
 					// format==='cjs' && replace({
 					// 	[`module.exports = ${rollupName};`]: '',