perf(sh): load main module in-process when possible

Author: zkat

lib/commands/shell.js

@@ -30,24 +30,24 @@ async function shell (argv, opts) {
   }
 
   function launchShell (argv, opts) {
-    // TODO - remove argv._.length check when next clause can be made to
-    //        work with `esm`.
-    if (argv._.length || (opts.nodeArg && opts.nodeArg.length)) {
+    if (opts.nodeArg && opts.nodeArg.length) {
       cp.spawnSync(
         process.argv[0],
         ['-r', require.resolve('esm'), '-r', require.resolve('../node/index.js'), ...(opts.nodeArg || []), ...argv._.slice(1)],
         { stdio: 'inherit' }
       )
     } else if (argv._.length > 1) {
-      // TODO - try to hook up to `esm`
       require('../node/index.js')
-      const Module = require('module')
-      process.argv = [
-        process.argv[0],
-        path.resolve(argv._[1]),
-        ...argv._.slice(2)
-      ]
-      Module.runMain()
+      const Module = module.constructor
+      const fname = path.resolve(argv._[1])
+      const mod = new Module(fname, null)
+      process.mainModule = mod
+      mod.id = '.'
+      try {
+        mod.load(fname)
+      } catch (err) {
+        delete Module._cache[fname]
+      }
     } else {
       require('../node/index.js')
       const { createRepl } = require('../node/repl.js')