feat: use --block-scoping for Hermes instead of Babel transform

Author: ChALkeR

bin/index.js

@@ -19,7 +19,7 @@ import { glob as globImplementation } from '../src/glob.cjs'
 const DEFAULT_PATTERNS = [`**/?(*.)+(spec|test).?([cm])[jt]s?(x)`] // do not trust magic dirs by default
 const bundleOpts = { pure: true, bundle: true, esbuild: true, ts: 'auto' }
 const bareboneOpts = { ...bundleOpts, barebone: true }
-const hermesA = ['-Og', '-Xmicrotask-queue']
+const hermesA = ['-Og', '-Xmicrotask-queue', '--block-scoping']
 const denoA = ['run', '--allow-all'] // also will set DENO_COMPAT=1 env flag below
 const denoT = ['test', '--allow-all']
 const nodeTS = process.features.typescript ? 'auto' : 'flag'

bundler/bundle.js

@@ -143,7 +143,7 @@ export const init = async ({ platform, jest, flow, target, jestConfig, outdir, e
         compact: false,
         babelrc: false,
         configFile: false,
-        plugins: ['@babel/plugin-transform-block-scoping', '@babel/plugin-transform-classes'],
+        plugins: ['@babel/plugin-transform-classes'],
       })
       return result.code
     })
@@ -154,7 +154,6 @@ const hermesSupported = {
   arrow: false,
   class: false, // we get a safeguard check this way that it's not used
   'async-generator': false,
-  'const-and-let': false, // have to explicitly set for esbuild to not emit that in helpers, also to get a safeguard check
   'for-await': false,
 }
 

bundler/package.json

@@ -73,7 +73,6 @@
   },
   "optionalDependencies": {
     "@babel/core": "^7.0.0",
-    "@babel/plugin-transform-block-scoping": "^7.0.0",
     "@babel/plugin-transform-classes": "^7.0.0",
     "flow-remove-types": "^2.242.0"
   },