Preserve execArgv with ts-node arguments (#760)

src/bin.ts

@@ -139,13 +139,15 @@ const EVAL_FILENAME = `[eval].ts`
 const EVAL_PATH = join(cwd, EVAL_FILENAME)
 const EVAL_INSTANCE = { input: '', output: '', version: 0, lines: 0 }
 
+// Prepend `ts-node` arguments to CLI for child processes.
+process.execArgv.unshift(__filename, ...process.argv.slice(2, process.argv.length - args._.length))
+process.argv = [process.argv[1]].concat(args._.length ? resolve(cwd, args._[0]) : []).concat(args._.slice(1))
+
 // Execute the main contents (either eval, script or piped).
 if (code) {
   evalAndExit(code, isPrinted)
 } else {
   if (args._.length) {
-    process.argv = ['node'].concat(resolve(cwd, args._[0])).concat(args._.slice(1))
-    process.execArgv.unshift(__filename)
     Module.runMain()
   } else {
     // Piping of execution _only_ occurs when no other script is specified.

src/index.spec.ts

@@ -260,6 +260,15 @@ describe('ts-node', function () {
         return done()
       })
     })
+
+    it('should preserve `ts-node` context with child process', function (done) {
+      exec(`${BIN_EXEC} tests/child-process`, function (err, stdout) {
+        expect(err).to.equal(null)
+        expect(stdout).to.equal('Hello, world!\n')
+
+        return done()
+      })
+    })
   })
 
   describe('register', function () {

tests/child-process.ts

@@ -0,0 +1,4 @@
+import { join } from 'path'
+import { fork } from 'child_process'
+
+fork(join(__dirname, 'hello-world.ts'))