feat(compiler-core): switch to @babel/parser for expression parsing

This enables default support for parsing bigInt, optional chaining
    and nullish coalescing, and also adds the `expressionPlugins`
    compiler option for enabling additional parsing plugins listed at
    https://babeljs.io/docs/en/next/babel-parser#plugins.

packages/template-explorer/index.html

@@ -6,14 +6,11 @@
 <div id="source" class="editor"></div>
 <div id="output" class="editor"></div>
 
-<script src="https://unpkg.com/acorn@7.1.0/dist/acorn.js"></script>
 <script src="https://unpkg.com/estree-walker@0.8.1/dist/estree-walker.umd.js"></script>
 <script src="https://unpkg.com/source-map@0.6.1/dist/source-map.js"></script>
 <script src="https://unpkg.com/monaco-editor@0.18.1/min/vs/loader.js"></script>
-<script src="./dist/template-explorer.global.js"></script>
 <script>
 window._deps = {
-  acorn,
   'estree-walker': estreeWalker,
   'source-map': sourceMap
 }
@@ -24,6 +21,7 @@ require.config({
   }
 })
 </script>
+<script src="./dist/template-explorer.global.js"></script>
 <script>
 require(['vs/editor/editor.main'], init /* injected by build */)
 </script>

packages/template-explorer/local.html

@@ -6,14 +6,12 @@
 <div id="source" class="editor"></div>
 <div id="output" class="editor"></div>
 
-<script src="../../node_modules/acorn/dist/acorn.js"></script>
 <script src="../../node_modules/estree-walker/dist/estree-walker.umd.js"></script>
 <script src="../../node_modules/source-map/dist/source-map.js"></script>
 <script src="../../node_modules/monaco-editor/min/vs/loader.js"></script>
-<script src="./dist/template-explorer.global.js"></script>
 <script>
 window._deps = {
-  acorn,
+  // @babel/parser is injected by the bundle
   'estree-walker': estreeWalker,
   'source-map': sourceMap
 }
@@ -24,6 +22,7 @@ require.config({
   }
 })
 </script>
+<script src="./dist/template-explorer.global.js"></script>
 <script>
 require(['vs/editor/editor.main'], init /* injected by build */)
 </script>

packages/template-explorer/src/index.ts

@@ -4,6 +4,9 @@ import { compile as ssrCompile } from '@vue/compiler-ssr'
 import { compilerOptions, initOptions, ssrMode } from './options'
 import { watchEffect } from '@vue/runtime-dom'
 import { SourceMapConsumer } from 'source-map'
+import { parse } from '@babel/parser'
+
+window._deps['@babel/parser'] = { parse }
 
 declare global {
   interface Window {